Expansion Valve

ABSTRACT

An expansion valve for reducing a pressure of a fluid flowing through the expansion valve along a fluid flow path has: at least one fluid inlet and at least one fluid outlet, a first valve element with at least one first channel structure, a second valve element with at least one second channel structure and a third channel structure, wherein the first and second valve elements are movable relative to each other, wherein, in a first position of the valve elements, the first and second channel structures are aligned with each other and form a first fluid flow path having a first flow resistance between the fluid inlet and the fluid outlet, and wherein in a second position of the valve elements, the first and third channel structures are aligned with each other and form a second fluid flow path having a second flow resistance.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of copending International Application No. PCT/EP2017/081703, filed Dec. 6, 2017, which is incorporated herein by reference in its entirety, and additionally claims priority from German Application No. 102016224283.0, filed Dec. 6, 2016, and from German Application No. 102017205562.6, filed Mar. 31, 2017, which are both incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

The present invention relates to expansion valves for reducing a pressure of a fluid flowing through the expansion valve along a fluid flow path.

Expansion valves can be used, for example, in refrigeration cycles. FIG. 8 shows such a refrigeration cycle 81 as it is known in known technology. The refrigeration cycle 81 has a condenser 82 and an evaporator 83. Between the condenser 82 and the evaporator 83 there is a local constriction 84 a, 84 b of the flow area which leads to a reduction in the fluid pressure and causes an increase in volume or expansion of the fluid flowing through. This local constriction 84 a, 84 b is functionally called throttle or expansion valve.

In the simplest case, a piece of pipe with a very small inner diameter acts as an unregulated, non-adjustable expansion element, which is then typically referred to as throttle capillary 84 b.

Cost-effective throttle capillaries may be used in systems with low refrigerating capacity, such as household refrigerator-freezer combinations.

More complex, controllable expansion valves 84 a are continuously variable valves which allow the fluid flowing through to be adjusted. These may be used for systems with a higher refrigerating capacity.

A fundamental problem with expansion valves for low refrigerating capacities is the small mass flow of refrigerant to be continuously dosed which places extraordinary demands on the precision of a continuously adjustable valve.

For this reason, often the solution is not to use a continuously adjustable valve but a switching valve which is then temporarily completely open or closed, i.e. operated in the sense of pulse width modulation. However, this procedure is not considered to be favorable in terms of both energy and system behavior.

An expansion valve for low refrigerating capacities can also be referred to as a micro expansion valve.

In DE 10 2011 004 109 A1, for example, an expansion valve with an infinitely variable perforated orifice is described. The flow through the orifice is controlled by means of an eccentric cover plate which can vary the opening cross-section of the orifice continuously. However, very high demands are placed on the precision of the orifice and on the precision of the infinitely variable drive, which leads to increased production costs.

As an alternative to the perforated orifice mentioned above, channels are known through which the fluid flows. Wth the perforated orifice, the deceleration and thus the expansion of the fluid is mainly caused by a turbulent flow at the edge of the orifice. In channels, however, when the fluid flows through the channels, additional friction losses occur along the walls of the channels, since the channels exhibit a much longer extension compared to the orifice so that the fluid can spread over the entire length of the channel and is slowed down due to the friction losses.

An expansion valve with channels, for example, is proposed in DE 31 08 051 A1. An expansion valve that can be switched in discrete switching stages is described here. Several plates are disposed on top of one another, whereby radial channels are formed between the plates through which the fluid can flow. A piston is arranged in the middle of the plates which is movable in axial direction in order to allow the fluid to flow through the individual channels. Due to the individual plates stacked on top of one another in the axial direction in combination with the piston movable in the axial direction, this expansion valve has a complex structure and a large axial height. This expansion valve is therefore less suitable for units with low refrigerating capacities, where as a rule only a very small installation space is usually available.

It may now occur that particles are contained in the fluid flowing through the expansion valve. These particles can block the expansion valve or individual channels of the expansion valve, which in turn can lead to a (partial) failure of the expansion valve.

EP 3 124 837 A1 therefore proposes to provide a circumferential groove on a valve body with several shielding parts in the form of projections. However, the production of the many individual projections is complex. Apart from this, in the document itself, it has already been recognized that certain contaminations, as for example hair, cannot be adequately held back by these shielding parts.

SUMMARY

According to an embodiment, an expansion valve for reducing a pressure of a fluid flowing through the expansion valve along a fluid flow path may have: at least one fluid inlet and at least one fluid outlet, a first valve element having at least one first channel structure, and a second valve element having at least one second channel structure and one third channel structure, wherein the first valve element and the second valve element are movable relative to each other, wherein, in a first position of the valve elements, the first channel structure and the second channel structure are aligned with each other and form a first fluid flow path having a first flow resistance between the fluid inlet and the fluid outlet, wherein, in a second position of the valve elements, the first channel structure and the third channel structure are aligned with each other and form a second fluid flow path having a second flow resistance differing from the first flow resistance between the fluid inlet and the fluid outlet, and wherein the second channel structure has a first variable or constant flow area, and wherein the third channel structure has a second variable or constant flow area differing from the first flow area, wherein the different flow areas oppose different flow resistances to the fluid and throttle the flow rate of the fluid to different extents.

Another embodiment may have a refrigerator and/or freezer having an inventive expansion valve as mentioned above.

The expansion valve according to the invention is configured to reduce a pressure of a fluid flowing through the expansion valve along a fluid flow path. The expansion valve has, inter alia, at least one fluid inlet through which the fluid can flow into the expansion valve and at least one fluid outlet through which the fluid can flow out of the expansion valve. The expansion valve also has a first valve element with at least a first channel structure. The expansion valve further comprises a second valve element having at least a second channel structure and a third channel structure. According to the invention, the first valve element and the second valve element are movable relative to each other, wherein in a first position of the valve elements, the first channel structure and the second channel structure are aligned with each other and form a first fluid flow path having a first flow resistance between the fluid inlet and the fluid outlet. In a second position of the valve elements, the first channel structure and the third channel structure are aligned with each other and form a second fluid flow path with a second flow resistance different from the first flow resistance between the fluid inlet and the fluid outlet.

Wth the expansion valve according to the invention, thus, at least two different switch positions can be achieved. Depending on the switch position, this results in a different fluid flow path. The fluid flow paths exhibit different flow resistances. For example, a flow resistance can result from a length of the channel structure flowed through, the cross-section of the channel structure flowed through not being necessarily uniform along the channel length, a change in the cross-section or the channel course flowed through, a geometric cross-sectional shape, a roughness of the surface of the walls of the channel structure flowed through, or from a combination of these parameters. The different flow resistances throttle the flow of the fluid to different extents. The throttling effect can be adjusted by means of a variation the above parameters. The expansion valve according to the invention can cause a complete throttling in a switch position so that the flow of the fluid from the fluid inlet to the fluid outlet is almost completely blocked. For example, in another switch position, the expansion valve according to the invention may exhibit no significant throttling so that the fluid can flow almost unhindered from the fluid inlet to the fluid outlet. The expansion valve can provide any throttle stage, i.e. between complete blocking and complete flow capability. As mentioned above, this is possible by means of a variation of the channel structure parameters. When the fluid flows through the expansion valve according to the invention, in addition to throttling the flow rate, there is a pressure drop in the fluid pressure, i.e. the fluid relaxes. The fluid can evaporate at least partially, and the temperature of the fluid can drop at the same time. The amount of pressure drop, as well as the amount of throttling of the flow rate, is determined by the throttling stages, i.e. the flow resistance, of the individual channel structures. The invention thus achieves the integration of different flow resistances together with a switchable distributor within a single expansion valve. This can considerably reduce the installation space consumed compared to distribution circuits with separate throttles or capillaries. In addition, compared to the known infinitely variable perforated orifices, considerably lower demands are placed on the precision of the drive, which in turn considerably reduces the manufacturing costs.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are shown in the drawing and are explained below, wherein:

FIG. 1A shows a first embodiment of an expansion valve according to the invention in an exploded view and in a first switch position;

FIG. 1B shows the expansion valve of the first embodiment in an assembled state and in a first switch position;

FIG. 1C shows the first embodiment of the expansion valve according to the invention in an exploded view and in a second switch position;

FIG. 1D shows the expansion valve of the first embodiment in an assembled state and in a second switch position;

FIG. 2A shows a second embodiment of an expansion valve according to the invention in an exploded view and in a first switch position;

FIG. 2B shows the expansion valve of the second embodiment in an assembled state and in a first switch position;

FIG. 3A shows an embodiment of an expansion valve according to the invention in accordance with the first embodiment in an exploded view and in a first switch position, wherein the channel structures of the second valve element are connected in series;

FIG. 3B shows the expansion valve of FIG. 3A in an assembled state;

FIG. 4A shows and embodiment an expansion valve according to the invention in accordance with the second embodiment in an exploded view and in a first switch position, wherein the channel structures of the second valve element are connected in series;

FIG. 4B shows the expansion valve of FIG. 4A in an assembled state;

FIG. 5A shows an embodiment of an expansion valve according to the invention in accordance with the first embodiment in an exploded view and in a first switch position, wherein the channel structures of the second valve element can be switched parallel to one another;

FIG. 5B shows the expansion valve of FIG. 5A in an assembled state;

FIG. 6A shows an embodiment of an expansion valve according to the invention in accordance with the second embodiment in an exploded view and in a first switch position, wherein the channel structures of the second valve element can be switched parallel to one another;

FIG. 6B shows the expansion valve of FIG. 6A in an assembled state;

FIG. 7 shows a schematic block diagram for one form of wiring of individual flow resistances;

FIG. 8 shows a known refrigeration cycle with a fluid expansion point as used in known technology;

FIG. 9 shows an embodiment of an expansion valve according to the invention;

FIG. 10 shows a further embodiment of expansion valve according to the invention;

FIG. 11 shows a top view of a valve element with several throttle channel structures and filter channel structures;

FIG. 12 shows a schematic view of a configuration possibility for filter channel structures;

FIG. 13 shows an embodiment of the arrangement of throttle channel structures and filter channel structures;

FIG. 14 shows a further embodiment of the arrangement of throttle channel structures and filter channel structures;

FIG. 15 shows a further embodiment of the arrangement of throttle channel structures and filter channel structures;

FIG. 16 shows a further embodiment of the arrangement of throttle channel structures and filter channel structures;

FIG. 17 shows an embodiment of bypass channel structures;

FIG. 18 shows an embodiment of a means of reducing the flow velocity;

FIG. 19A shows an embodiment of a structural configuration of a lift-off function of two valve elements;

FIG. 19B shows an illustration of the lift-off function;

FIG. 19C shows an embodiment of a structural configuration of a lift-off function of the first and second parts of the two-part second valve element;

FIG. 20A shows an embodiment of a structural realization of a reversal of flow direction;

FIG. 20B shows a further embodiment of a structural realization of a reversal of flow direction;

FIG. 21A shows a diagram for illustrating switching stages with linearly increasing flow rate;

FIG. 21B shows a diagram for illustrating switching stages with linearly decreasing flow rate;

FIG. 21C shows a diagram for illustrating switching stages with an arbitrarily arranged flow rate; and

FIG. 21D shows a diagram for illustrating the switching stages which are arranged relative to their throttling rate according to their respective use frequency.

DETAILED DESCRIPTION OF THE INVENTION

In the following, some embodiments of the invention are described in more detail with reference to the Figures, wherein elements with the same or similar function are provided with the same reference signs. In addition, everything specified with reference to a particular embodiment shall also apply to all other embodiments. In the following, in order to facilitate reading the description, many features are explained with reference to FIGS. 1A to 1D. However, it goes without saying that all these features shall similarly also apply to the embodiments shown in the other FIGS. 2A to 21D.

In the following, channel structures are described on the basis of two exemplary channel structures, namely a first channel structure 22 a, 22 b and a second channel structure 23 a, 23 b. However, more than two channel structures can also be conceivable. Each channel structure 22 a, 22 b, 23 a, 23 b may have a radially (relative to the axis of rotation) extending portion 22 b, 23 b. Each channel structure 22 a, 22 b, 23 a, 23 b may have a portion 22 a, 23 a extending axially (relative to the axis of rotation). The respective axially extending portion 22 a, 23 a and/or the respective radially extending portion 22 b, 23 b may extend linearly or non-linearly, e.g. curved or in the form of one or more curves (see e.g. FIG. 13), from a center of a valve element 10, 20 to an outer surface of the respective valve element 10, 20.

Each of the channel structures 22 a, 22 b, 23 a, 23 b can provide a throttling function to throttle the fluid. Therefore, the channel structures 22 a, 22 b, 23 a, 23 b can also be called throttle channel structures. Since in particular the radially extending portions 22 b, 23 b can provide different throttle stages, the radially extending portions 22 b, 23 b are particularly referred to as throttle channel structures in this document.

When fluid is referred to in the following, it can mean both a liquid and a gas. Mixed forms of partly gaseous and liquid states of the fluid can also be meant thereby. In general, the fluid can be present in all occurring aggregate states in the meaning of the present disclosure. For example, the fluid may be in a substantially liquid aggregate state upstream of the expansion valve, while it may be in a substantially gaseous state downstream of the expansion valve (possibly with a downstream evaporator). The fluid can be a refrigerant, e.g. R600 a or R134 a.

FIGS. 1A and 1B show a first embodiment of an expansion valve 100 according to the invention. The expansion valve 100 has at least one fluid inlet 101 and at least one fluid outlet 102.

The expansion valve 100 also has a first valve element 10 with at least a first channel structure 11. In addition, the expansion valve 100 has a second valve element 20. The second valve element 20 can consist of two parts 20 a, 20 b as it is exemplarily shown here. Further embodiments provide that the second valve element 20 is configured in one piece. The second valve element 20 has at least a second channel structure 22 a, 22 b and a third channel structure 23 a, 23 b.

Channel structures in general, and specifically the shown channel structures 11, 22 a, 22 b, 23 a, 23 b are structures provided in the respective valve element 10, 20, e.g. in the form of recesses which provide a flow path for a fluid flowing through.

The first valve element 10 and the second valve element 20 are movable relative to one another. As particularly shown in FIG. 1B, in a first position of the valve elements 10, 20, the first channel structure 11 and the second channel structure 22 a, 22 b are aligned with one another and form a first fluid flow path 110 with a first flow resistance between the fluid inlet 101 and the fluid outlet 102.

FIGS. 1C and 1D show a second position of the valve elements 10, 20. In this second position of valve elements 10, 20, the first channel structure 11 and the third channel structure 23 a, 23 b are aligned with one another and form a second fluid flow path 111 with a second flow resistance different from the first flow resistance between the fluid inlet 101 and the fluid outlet 102.

FIG. 1C, for example, shows that at least one portion 23 b of the third channel structure 23 a, 23 b leads into a for example circumferentially running channel structure 55 which extends up to the fluid outlet 102. Accordingly, the fluid flows through this portion 23 b of the third channel structure 23 a, 23 b and the circumferential channel structure 55 which is partially covered in FIG. 1D, to the fluid outlet 102.

At least one portion 22 b of the second channel structure 22 a, 22 b also leads into the circumferential channel structure 55. So to speak, the circumferential channel structure 55 connects the channel structures 22 a, 22 b, 23 a, 23 b formed in the second valve element 20 with one another and forms a common feed to the fluid outlet 102. The amount of the total flow resistance for the fluid flowing through can be composed of a) the flow resistance of the first channel structure 11 of the first valve element 10, b) the flow resistance of the respective channel structure 22 a, 22 b, 23 a, 23 b of the second valve element 20, and c) the flow resistance of the circumferential channel structure 55.

FIGS. 1B and 1D show different switch positions of the expansion valve 100. These switch positions can be achieved by means of the aforementioned relative movement between the first valve element 10 and the second valve element 20. The expansion valve 100 can therefore switch back and forth between different switch positions or switching stages.

As can be seen particularly in FIGS. 1A and 10, the second valve element 20 can also have further channel structures 24 a, 24 b; 25 a, 25 b in addition to the second and third channel structures 22 a, 22 b; 23 a, 23 b. These are described in more detail below.

The individual channel structures can have different flow areas, which are not necessarily constant along the channel length, i.e. a channel structure can have a variable flow area. According to the conceivable embodiments of the invention, the flow areas of the individual channel structures can either be constant or variable.

For example, a variable flow area can be achieved by changing the geometric cross-section of the respective channel structure at least once over its channel length. Thus, a channel structure with a variable flow area, for example, can have a first flow area at a first point and a second flow area at a second point that differs from the first flow area.

For example, a channel structure can be configured such that the flow area increases or decreases along the fluid flow direction. According to another conceivable example, the channel structure at the beginning and at the end may have a first flow area and in between a second (smaller or larger) flow area, e.g. in the form of a constriction and the like.

The flow area of a channel structure can influence the flow rate of a fluid flowing through this channel structure. This means, for example, that with the same channel length, a smaller volume of a channel structure causes a smaller flow area of this channel structure, which counters the flowing fluid with a larger flow resistance, whereby the flow rate of the fluid can be throttled.

In addition to the flow area, the shape of a channel structure can also significantly influence its flow resistance. Thus, according to the invention, channel structures with a round shape are conceivable. These can be produced by drilling, for example. However, it is also conceivable that the channel structures have a rectangular shape. These can be produced, for example, by milling. In principle, other geometric forms of the channel structures are also conceivable, e.g. triangular, round, semicircular or polygonal. For example, a triangular channel structure may have a higher flow resistance than a square channel structure.

Irrespective of whether the different flow areas are achieved by varying the geometric cross-section and/or by varying the geometric shape of the channel structures, different flow areas counter the fluid with different flow resistances and thus throttle the flow rate of the fluid to different degrees. Accordingly, channel structures with different flow areas can also be specifled as different throttle stages for throttling the flow rate.

At the same time, the throttling also causes a decrease of the pressure of the fluid flowing through, i.e. the pressure of the fluid at the fluid outlet 102 is lowered compared to the pressure of the fluid at the fluid inlet 101. When the fluid flows through the expansion valve 100, the fluid relaxes. In addition, it can also evaporate, at least partially.

The flow rate Q is essentially characterized by the volume flow of a fluid flowing through a certain flow area, according to the known formula

$Q = {\overset{.}{V} = \frac{dV}{dt}}$

Thereby, the mass flow {dot over (m)} relates to the flow rate Q via the relation

$\overset{.}{m} = {\frac{dm}{dt} = {\rho \cdot \overset{.}{V}}}$

wherein ρ is the density of the fluid.

As mentioned above, the individual channel structures can thus be specified as throttle stages, by means of which the expansion valve 100 can throttle the flow rate or the mass flow of the fluid flowing through.

According to embodiments of the invention, the second channel structure 22 a, 22 b may have a first flow area and the third channel structure 23 a, 23 b may have a second flow area different from the first flow area. Thus, the expansion valve 100 has at least two different throttle stages.

According to the invention, the throttle stages can have throttle rates between almost 100% and almost 0%. The relative value of the throttle rates thereby refers to the throttling of the flow rate of the fluid between the fluid inlet 101 and the fluid outlet 102 relative to a period of time Δt.

For example, a throttle rate of 100% means that the fluid flow rate from fluid inlet 101 to fluid outlet 102 is almost zero or equal to zero within this period of time Δt The expansion valve 100 thus blocks the flow of the fluid. The expansion valve 100 can thus provide a “stop function” where the flow of the fluid is stopped. Due to leakages of valves which are known to the skilled person and often occur, the flow rate can only be almost 0%, i.e. slightly above 0%.

For example, a flow rate here can be between 0% and 5% for any leakages that may occur.

On the contrary, a throttling rate of almost 0% means that the fluid flow is almost not throttled, i.e. the fluid flow rate from fluid inlet 101 to fluid outlet 102 within the period of time Δt is almost 100%. Due to flow and friction losses known to the skilled person within the channel structures flowed through, the flow rate as a rule will only be able to reach almost 100%, i.e. slightly below 100%. For example, a flow rate here can be between 95% and 100%.

The expansion valve 100 can thus provide an “open function” or also a “free flow function” in which a flow of the fluid is possible almost unhindered. In this case, there is no significant throttling within the expansion valve 100.

As mentioned introductorily, the expansion valve 100 according to the invention has at least two throttling stages, i.e. the flow resistance of the first flow path in the first switch position differs from the flow resistance of the second flow path in the second switch position. At least, one of the two flow resistances can be configured in such a way that the expansion valve 100 has no significant throttling in the respective switch position. This means that at least one of the two flow paths (first switch position or second switch position) forms an above mentioned “open function” or “free flow function”.

Said “open function” can be realized, for example, by the first and second channel structures 11; 22 a, 22 b forming the first fluid flow path or the first and third channel structures 11; 23 a, 23 b forming the second fluid flow path being configured as a continuous opening through the first and second valve elements 10; 20, e.g. a bore of the same diameter, wherein said opening does not have a significant throttling. This means that the expansion valve 100 has a throttling rate of almost 0%, or a throttling rate between 0% and a maximum of 5%.

An above mentioned “stop function” can be realized, for example, by aligning the first channel structure 11 in the first valve element 10 with none of the channel structures 22 a, 22 b, 23 a, 23 b of the second valve element 20. This can be achieved, for example, by moving the first valve element 10 to a (not explicitly shown) third switch position which can be, for example, between the first switch position (FIG. 1B) and the second switch position (FIG. 1D). The first channel structure 11 of the first valve element 10 thus no longer leads into a further channel structure in the second valve element 20 but directly onto the surface 28 (FIGS. 1A, 1D) of the second valve element 20. The fluid is thus no longer directed to the fluid outlet 102, i.e. the flow of the fluid is thereby blocked or interrupted.

When, in the meaning of the present disclosure, it is stated that a fluid flow is interrupted between the fluid inlet 101 and the fluid outlet 102, this means that the fluid flow is to be deliberately interrupted by means of the position of the valve elements 10, 20 relative to one another, irrespective of whether there is an unwanted or parasitic flow of the fluid due to possible leakages in valves and the like. The flow of the fluid to be interrupted is the direct flow through the channel structures.

The first valve element 10 can be moved relative to the second valve element 20 by means of a stepper motor, for example. One of the two valve elements 10, 20 is thereby driven by the stepper motor and moved relative to the other of the two valve elements 10, 20.

In addition, gears can be provided that reduce or step up the drive of the stepper motor accordingly.

If the stop function in the third switch position, as mentioned above, is between the first and the second switch position, this has particular advantages with regard to possible energy savings. Imagine a starting position of the valve element 10, 20 connected to the stepper motor being the third switch position. Then the stepper motor would not have to move the valve element 10, 20 over the entire distance from the first switch position to the second switch position (or back), but in this case it is sufficient to move the valve element 10, 20 only from the third switch position to the first or second switch position. Since the third switch position is between the first and second switch position, the stepper motor only has to cover half the distance.

In the embodiment shown in FIGS. 1A to 1D, the first valve element 10 could be driven by the stepper motor. An alternative embodiment in which the second valve element 20 can be driven is described below with reference to FIGS. 2A and 2B.

First of all, however, the first embodiment is to be described further. As illustrated in FIGS. 1A and 10, the second valve element 20 in this embodiment is configured of two parts, i.e. the second valve element has a first part 20 b and a second part 20 a.

The first part 20 b of the second valve element 20 thereby exhibits at least one portion 22 b, 23 b of the second and third channel structures 22 a, 22 b; 23 a, 23 b. This means that these portions 22 b, 23 b of the channel structures are formed in the first part 20 b of the second valve element 20. As will be described later in more detail, the channel structures 22 a, 22 b; 23 a, 23 b and in particular their portions 22 b, 23 b can also be referred to as throttle channel structures. For example, the portion 22 b of the second channel structure 22 a, 22 b may also be referred to as a first throttle channel portion 22 b, and the portion 23 b of the third channel structure 23 a, 23 b may also be referred to as a second throttle channel portion 23 b.

The first part 20 b of the second valve element 20 in addition may have at least one fluid outlet 102. The throttle channel structures or portions 22 b, 23 b of the second and third channel structures are each connected within the first part 20 b of the second valve element 20 to the fluid outlet 102, for example, by means of the circumferential channel structure 55. However, it is also conceivable that several fluid outlets are arranged in the second valve element 20 or in the first part 20 b of the second valve element 20.

Advantageously, a seal is arranged between the first part 20 b of the second valve element 20 and the second part 20 a of the second valve element 20, which seal fluidly seals the second and third channel structures 22 b, 23 b formed in the first part 20 b of the second valve element 20 against one another. This can in particular be a Teflon seal, as it is particularly temperature-resistant, pressure-resistant and age-resistant.

However, a sealing of the two parts 20 a, 20 b of the valve element 20 can also be achieved, for example, by gluing, screwing or welding the two parts 20 a, 20 b together, e.g. by friction or laser welding.

The valve elements 10, 20 can in principle have various geometric shapes, i.e. the valve elements 10, 20 can, for example, be configured in the form of a cylinder, a cube, a sphere, a hemisphere, a pyramid, a prism and the like.

The channel structures 11, 22 a, 22 b, 23 a, 23 b formed in the respective valve elements 10, 20 thereby may extend at least in sections in a radial direction and/or at least in sections in an axial direction. For example, if the two valve elements 10, 20 are rotatable relative to one another along an axis of rotation, an axial direction and a radial direction may be in relation to this axis of rotation.

Some embodiments of the invention provide that the first valve element 10 and the second valve element 20 are each cylindrical valve elements, wherein the first channel structure 11 in the first valve element 10 extends at least in sections in the axial and/or radial direction and/or wherein the second and third channel structures 22 a, 22 b; 23 a, 23 b in the second valve element 20 extend at least in sections 22 b, 23 b in the radial and/or axial direction.

Further examples of the invention provide that the first valve element 10 and the second valve element 20 are each circular cylindrical valve elements and the first valve element 10 is concentrically aligned in the axial direction with the second valve element 20.

This shall be explained below with reference to FIGS. 1A to 1D only exemplarily. As can be seen exemplarily in said Figures, the first valve element 10 and the second valve element 20 can each be exemplarily shown here as cylindrical valve elements.

It should be mentioned here that a cylinder, by definition, is characterized in that an even curve in a plane is shifted by a fixed distance along a straight line that is not contained in this plane. Two corresponding points of the curves and of the shifted curve, respectively, are connected by a distance. The totality of these parallel distances forms the corresponding cylinder surface. The curve or the resulting lateral surface can have any shape.

The embodiment shown is a special form of a cylinder, namely a circular cylinder, i.e. the first valve element 10 and the second valve element 20 are each of circular cylindrical design, wherein the first valve element 10 can be concentrically aligned in axial direction 33 (FIG. 1A) with the second valve element 20.

In the embodiment shown, the first channel structure 11 in the first valve element 10 extends at least in sections in the axial direction 33 (FIG. 1A). The first channel structure 11 extends completely through the first valve element 10. In production, this can be achieved, for example, by the fact that a bore is introduced through the first valve element 10 in the axial direction 33 of the same.

In another conceivable embodiment, the first channel structure 11 could extend in the radial direction 34 in the first valve element 10. This is exemplarily indicated in FIG. 1A with the first channel structure 11′ shown in dashed lines. In production, this can be achieved, for example, by the fact that a bore is introduced through the first valve element 10 in the radial direction 34 of the same. It would also be conceivable that the radially extending first channel structure 11′ shown in dashed lines would be milled, sawn, lasered or cut from the lower side 12 of the first valve element 10 into the same by means of separating processes and/or embossed, molded by means of forming processes and/or produced directly by means of forming processes such as injection molding.

It would also be conceivable that the first channel structure 11 extends both in sections in radial direction 34 and in sections in axial direction 33.

Alternatively or additionally, the second and third channel structures 22 a, 22 b, 23 a, 23 b in the second valve element 20 extend at least in sections in the radial direction 34 (FIG. 1A). More precisely, the throttle channel structures or portions 22 b, 23 b of the channel structures 22 a, 22 b, 23 a, 23 b arranged in the first part 20 b of the second valve element 20 extend at least in sections in the radial direction 34. In production, this can be realized, for example, in that the throttle channel structures or portions 22 b, 23 b of the channel structures 22 a, 22 b, 23 a, 23 b are milled, sawn, lasered or cut from above into the second valve element 20 by means of separating processes and/or are embossed, molded by means of forming processes and/or produced directly by means of forming processes such as injection molding. These are relatively simple method steps that facilitate production and can therefore significantly reduce unit costs.

It would also be conceivable that the second channel structure 22 a, 22 b and/or the third channel structure 23 a, 23 b extends at least in sections in the axial direction 33 through the second valve element 20 or the first part 20 b of the second valve element 20. The second channel structure 22 a, 22 b could have a different flow area than the third channel structure 23 a, 23 b.

The first valve element 10 has a surface 12 facing the second valve element 20 (FIGS. 1A and 10). The first valve element 10 and the second valve element 20 are movable relative to one another, namely in the plane E₁ shown and running parallel to said surface 12. The two valve elements 10, 20 can, for example, be moved translationally to one another in said plane E₁ and thus be shifted against one another.

In the embodiments shown, the first valve element 10 and the second valve element 20 can be rotated relative to one another so that a movement from the first position of the valve elements 10, 20 (FIG. 1B) to the second position of the valve elements 10, 20 (FIG. 1D) can be carried out by means of a rotation of the first valve element 10 relative to the second valve element 20. Thereby, either the first valve element 10 can be rotated relative to the second valve element 20, or the second valve element 20 can be rotated relative to the first valve element 10, e.g. by means of a stepper motor.

As shown in FIGS. 1A to 1D, the expansion valve 100 may have a cover 30. The cover 30 has a recess 31. The cover 30 is immovably connected to the second valve element 20. The first valve element 10 is movably arranged within this cover 30, or within the recess 31, relative to the second valve element 20, and thus also relative to the cover 30. In this case, the first valve element 10 can be arranged in the expansion valve 100 so that it can be moved, in particular rotated.

For this purpose, the expansion valve 100 has an axis 41 which can, for example, be non-rotatably mounted on the second valve element 20 and/or on the cover 30. The first valve element 10 is movably, in particular rotatably mounted on this axis 41 by means of a corresponding receptacle 42.

As shown in FIG. 1A, the axis 41 is centered, i.e. arranged in the center of the second valve element 20. The receptacle 42 of the first valve element 10 is also arranged centered in the first valve element 10. This means that the first valve element 10 and the second valve element 20 are arranged concentrically around said axis 41. Thus, the first valve element 10 and the second valve element 20 are arranged concentrically to one another.

However, it is also conceivable that the axis 41 is off-centered, i.e. not arranged in the center of the second valve element 20. Then in fact, the first valve element 10 would still be arranged concentrically to the axis 41. However, the first valve element 10 and the second valve element 20 would then no longer be arranged concentrically but eccentrically to one another. Such an arrangement is shown for example in FIGS. 9 and 10 which will be described in more detail later.

It would also be conceivable that the receptacle 42 in the first valve element 10 is offcentered, i.e. not arranged in the center of the first valve element 10. Then the first valve element 10 would not be arranged concentrically but eccentrically to the axis 41.

In the embodiment shown in FIG. 1A, a lower side surface 27 of the cover 30 facing the second valve element 20 is coupled with a surface 28 of the second valve element 20, e.g. glued. In this case, the cover 30 thus is arranged on the second valve element 20. The second valve element 20, together with the cover 30, can form a housing, in particular a fluid-tight housing.

However, it would also be conceivable that an inner wall 26 of the cover 30 is coupled with a laterally circumferential outer wall 29 a, 29 b of the second valve element 20. In this case, the second valve element 20 would fit inside the recess 31 of the cover 30. In addition, in this case, the second valve element 20 together with the cover 30 can also form a housing, in particular a fluid-tight housing. Advantageously, an additional cover (not shown here) would then be coupled with the lower side surface 27 of the cover 30.

Within the cover 30, e.g. the fluid inlet 101 may be arranged. As an alternative or in addition to the fluid inlet 101 within the cover 30, a fluid inlet 101′ may be provided in the second valve element 20 and/or in the not shown cap. In FIG. 1A, this optional fluid inlet 101′ is indicated with dashed lines. The fluid inlet 101 can also be arranged laterally within the cover 30. However, at least one fluid inlet should be provided to allow the fluid to be introduced into the recess 31 of the cover 30 to direct the fluid to the channel structures of the two valve elements 10, 20.

When the cover 30 is connected to the second valve element 20, the recess 31 of the cover 30 forms a fluid chamber 32 (FIG. 1B). The fluid can thus flow through the fluid inlet 101 into the fluid chamber 32 formed by the recess of the cover 30. By means of said cover 30 it can thus be ensured that the fluid is directed into the channel structures 11, 22 a, 22 b, 23 a, 23 b.

Moreover, this embodiment shows that the first valve element 10 is arranged before the second valve element 20, relative to the flow direction of the fluid from the fluid inlet 101 to the fluid outlet 102. Thus, the fluid first flows into the first channel structure 11 formed in the first valve element 10 and then, depending on the switch position of the expansion valve 100, into at least one of the channel structures 22 a, 22 b, 23 a, 23 b arranged in the second valve element 20.

FIGS. 2A and 2B show a further embodiment of an expansion valve 100 according to the invention.

Here, the expansion valve 100 also has a cover 30, however, with the difference that the cover 30 here is immovably connected to the first valve element 10 and the second valve element 20 is movably arranged within the cover 30 relative to the first valve element 10.

For this purpose, an axis 41 is non-rotatably fixed to the first valve element 10 and/or the housing 30. The second valve element 20 is also configured in two parts, wherein the first part 20 b and the second part 20 a are each mounted movably, in particular rotatably on said axis 41 by means of a corresponding receptacle 42.

As shown in FIG. 2A, the axis 41 is centered, i.e. arranged in the center of the first valve element 10. The receptacle 42 of the second valve element 20 is also arranged centered in the second valve element 20. This means that the first valve element 10 and the second valve element 20 are arranged concentrically around said axis 41. Thus, the first valve element 10 and the second valve element 20 are arranged concentrically to one another.

However, it is also conceivable that the axis 41 is off-centered, i.e. not arranged in the center of the first valve element 10. Then in fact, the second valve element 20 would still be arranged concentrically to the axis 41. However, the first valve element 10 and the second valve element 20 would then no longer be arranged concentrically but eccentrically to one another.

It would also be conceivable that the receptacle 42 in the second valve element 20 is off-centered, i.e. not arranged in the center of the second valve element 20. Then, the second valve element 20 would not be arranged concentrically but eccentrically to the axis 41.

In contrast to the first embodiment (FIGS. 1A to 1D), the second valve element 20 here is arranged before the first valve element 10, relative to the flow direction of the fluid from the fluid inlet 101 to the fluid outlet 102.

As mentioned above, the second valve element 20 is configured in two parts, wherein a first part 20 b of the second valve element 20 comprises the second and third channel structures 22 a, 22 b; 23 a, 23 b, and a second part 20 a of the second valve element 20 forms a closed cover of the second and third channel structures 22 a, 22 b; 23 a, 23 b. The channel structures 22 a, 22 b; 23 a, 23 b and in particular the radially extending portions 22 b, 23 b can also be referred to as throttle channel structures.

Furthermore, the first channel structure 11 in this embodiment simultaneously forms the fluid outlet 102 of the expansion valve 100.

FIG. 2B shows an assembled expansion valve 100 and the fluid flow path 112 resulting through the expansion valve 100. The fluid enters the expansion valve 100 through the fluid inlet 101, then flows through the channel structures 22 a, 22 b, 23 a, 23 b formed in the second valve element 20, and then exits the expansion valve 100 through the fluid outlet 101 formed by the first channel structure 11 formed in the first valve element 10.

In the embodiment shown in FIG. 2B, the expansion valve 100 is in a first switch position. More specifically, the two valve elements 10, 20 are in a first position relative to one another, in which first position the first channel structure 11 and the second channel structure 22 a, 22 b are aligned with each other and form a first fluid flow path 112 with a first flow resistance between the fluid inlet 101 and the fluid outlet 102.

In a second switch position, which is not explicitly shown here, the second valve element 20 would be turned by 180°, for example, in contrast to the first switch position shown in FIG. 2B. In this case, the first channel structure 11 and the third channel structure 23 a, 23 b would be aligned with one another and form a second fluid flow path with a second flow resistance different from the first flow resistance between the fluid inlet 101 and the fluid outlet 102.

Wth the exception of the just described structural differences of the embodiment shown in FIGS. 2A and 2B, the same applies to this embodiment as to the embodiments described above with reference to FIGS. 1A to 1D.

Therefore, the common mode of operation for all embodiments shown in FIGS. 1A to 2B shall be explained in more detail below. Both the expansion valve 100 according to the first embodiment (FIGS. 1A to 1D) and the expansion valve 100 according to the second embodiment (FIGS. 2A, 2B) are interconnections of the channel structures which can hereinafter also be referred to as individual connections.

Said individual connection is among other things characterized in that in the first and second positions of the valve elements 10, 20, exactly one of the second and third channel structures 22 a, 22 b; 23 a, 23 b of the second valve element 20 is fluidly coupled to the fluid outlet 102 to form a single fluid flow path 111, 112 between the fluid inlet 101 and the fluid outlet 102.

This means that exactly one of the second and third channel structures 22 a, 22 b; 23 a, 23 b of the second valve element 20 is aligned with the first channel structure 11 formed in the first valve element 10.

For an explanation in more detail, for this purpose, it shall be referred to FIG. 1A once again. As mentioned introductorily, the second valve element 20 may also have further channel structures 24 a, 24 b, 25 a, 25 b in addition to the second and third channel structures 22 a, 22 b, 23 a, 23 b. The first valve element 10, on the contrary, has only one channel structure, that is the first channel structure 11.

The two valve elements 10, 20 are moved relative to one another, e.g. by means of an above mentioned stepper motor, namely such that the first channel structure 11 of the first valve element 10 is aligned with only one channel structure 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b of the second valve element 20.

The individual channel structures 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b of the second valve element 20 have different flow areas. In addition, all channel structures 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, or at least their radially extending portions 22 b, 23 b, 24 b, 25 b, lead into a common channel structure 55.

Thus, the throttling of the flow rate on the one hand results from the individual length and the individual flow area of each individual channel structure 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, which is not necessarily constant or geometrically variable over the channel length, and on the other hand from the length and the flow area of the common channel structure 55. Thus, channel-specific fluid flow paths with individual throttling rates are formed.

The longer the fluid flow path covered by the fluid, the more a further criterion plays a decisive role in determining the individual throttle rate. The fluid flowing through a channel structure undergoes a friction on the surface of the walls of the respective channel structure, which additionally slows down the fluid. The individual channel structures can therefore be provided with a certain surface roughness according to the invention. Tests have shown that with the adjustment of the surface roughness, differences in the throttling rate of up to 10% were noticeable compared to fluidly smooth surface properties of the channel structures.

In addition to this individual connection just described, further embodiments provide a series connection and/or a parallel connection of the channel structures. A series connection of the channel structures of the first embodiment (FIGS. 1A to 1D) shall be described below with reference to FIGS. 3A and 3B.

The series connection is characterized, among other things, by the fact that the second channel structure 22 a, 22 b and the third channel structure 23 a, 23 b are connected to one another within the second valve element 20 at least in sections 22 b, 23 b, that is at least the throttle channel structures 22 b, 23 b of the respective channel structures 22 a, 22 b; 23 a, 23 b are connected to one another, wherein in the second position of the valve elements 10, 20, the second fluid flow path is composed of the second and the third channel structure 22 b, 23 b connected thereto, and in particular of the respective throttle channel structures 22 b, 23 b, and the second fluid flow path has a total flow resistance which is composed of the flow resistance of the second channel structure or the throttle channel structure 22 b and the flow resistance of the third channel structure connected thereto or the throttle channel structure 23 b.

Here, too, the second valve element 20 is again configured in two parts. In the first part 20 b, several different channel structures or throttle channel structures 22 b, 23 b, 24 b, 25 b, 26 b are formed, here for example a total of five. The individual channel structures or throttle channel structures 22 b, 23 b, 24 b, 25 b, 26 b are all fluidly connected to one another so that they form a long chain or series connection of several channel structures or throttle channel structures.

However, the expansion valve 100 has only one common fluid outlet 102 which is connected to the first or last channel structure or throttle channel structure 22 b from the series connection. Depending on which channel structure or throttle channel structure 22 b, 23 b, 24 b, 25 b, 26 b the fluid finally enters, the fluid has to cover different distances to the fluid outlet 102.

The total flow resistance is composed of the individual flow resistances of the channel structures passed through. Thereby, the individual channel structures, and in particular the throttle channel structures 22 b, 23 b, 24 b, 25 b, 26 b, can also have different flow areas which are not necessarily constant or geometrically variable over the channel length.

In the second part 20 a of the second valve element 20, correspondingly many, thus here also five, channel structures 22 a, 23 a, 24 a, 25 a, 26 a are formed which are aligned with the channel structures or throttle channel structures 22 b, 23 b, 24 b, 25 b, 26 b formed in the first part 20 b of the second valve element 20.

The first valve element 10 is rotatable relative to the second valve element 20 and has the first channel structure 11. The first channel structure 11 can now be aligned in different switching stages optionally to one of the channel structures 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, 26 a, 26 b formed in the second valve element 20. Depending on the selected switching stage, a different fluid flow path is formed, which the fluid flowing through covers to reach the fluid outlet 102.

One of these several possible switch positions is exemplarily shown in FIG. 3B. Here, the first valve element 10 is aligned with the second valve element 20 such that the first channel structure 11 is aligned with the sixth channel structure 26 a, 26 b.

The resulting fluid flow path is marked by the dash-lined arrow 121. The fluid thus enters the expansion valve 100 through the fluid inlet 101, then flows through the first channel structure 11, which is aligned with the sixth channel structure 26 a, 26 b, passes through all further channel structures or throttle channel structures 25 b, 24 b, 23 b, to then flowing through the first channel structure or throttle channel structure 22 b into the fluid outlet 102.

So to speak, the fluid meanders through the entire series connection of channel structures and is thereby correspondingly throttled.

A series connection of the second embodiment (FIGS. 2A and 2B) shall be described below with reference to FIGS. 4A and 4B.

This series connection is also characterized, among other things, in that the second channel structure 22 a, 22 b and the third channel structure 23 a, 23 b are connected to one another within the second valve element 20 at least in sections 22 b, 23 b,that is at least the throttle channel structures 22 b, 23 b are connected to one another, wherein in the second position of the valve elements 10, 20 the second fluid flow path is composed of the second and the third channel structure connected thereto, and in particular the throttle channel structure 22 b, 23 b, and the second fluid flow path has a total flow resistance which is composed of the flow resistance of the second channel structure, and in particular the throttle channel structure 22 b, and the flow resistance of the third channel structure connected thereto, and in particular the throttle channel structure 23 b.

Here, too, the second valve element 20 is again configured in two parts. In the first part 20 b, several, here exemplarily altogether five, different channel structures 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, 26 a, 26 b are formed. The individual channel structures 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, 26 a, 26 b, or the portions 22 b, 23 b, 24 b, 25 b, 26 b referred to as throttle channel structures, are all fluidly connected to one another so that they form a long chain or series connection of several channel structures.

In contrast to the series connection described above, however, it should be noted that each channel structure has a radial portion 22 b, 23 b, 24 b, 25 b, 26 b and an axial portion 22 a, 23 a, 24 a, 25 a, 26 a, which are also referred to as throttle channel structure. In the sectional view shown in FIG. 4A, only the axial portions 22 a and 26 a of the second and sixth channel structures are recognizable. The axial portions 23 a, 24 a, 25 a of the remaining channel structures are hidden in this sectional view and therefore only indicated by dashed lines.

The expansion valve 100 in turn has only one common fluid outlet 102, which also forms the first channel structure 11 of the first valve element 10.

The second valve element 20 is rotatable compared with the first valve element 10 and can now be rotated optionally into different switching stages, wherein in each switching stage a different one of the channel structures 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, 26 a, 26 b of the second valve element 20 is aligned with the first channel structure 11 of the first valve element 10. More precisely, depending on the switching stage, an axial portion 22 a, 23 a, 24 a, 25 a, 26 a of the respective channel structure of the second valve element 20 is aligned with the first channel structure 11 of the first valve element 10.

The fluid thereby enters the second valve element 20 through the radial portion or throttle channel structure 22 b of the second channel structure 22. Depending on which switch position is selected, the fluid flows through the corresponding further channel structures 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, 26 a, 26 b in addition to the second channel structure 22 a, 22 b. The fluid thus has to cover different distances to the fluid outlet 102. Depending on the selected switching stage, a different fluid flow path is formed which the fluid flowing through travels to reach the fluid outlet 102.

The total flow resistance is made up of the individual flow resistances of the channel structures passed through. The individual channel structures 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, 26 a, 26 b thereby can also have different flow areas which are not necessarily constant or geometrically variable over the channel length.

One of these several possible switch positions is exemplarily shown in FIG. 4B. Here, the second valve element 11 is arranged opposite the first valve element 10 such that the second channel structure 22 a, 22 b is aligned with the first channel structure 11.

The resulting fluid flow path is marked by the dash-lined arrow 122. Thereby, the fluid flows through the radial portion or the throttle channel structure 22 b of the second channel structure into the second valve element 20 and flows through the axial portion 22 a of the second channel structure 20 to the first channel structure 11 which at the same time is the fluid outlet 102.

In a further switch position not explicitly shown, the second valve element 20 would, for example, be turned by 180° in relation to the switch position shown in FIG. 4B. In this case, the axial portion 26 a of the sixth channel structure would be aligned with first channel structure 11 (=fluid outlet 102). The fluid would then enter the second valve element 20 through the radial portion or throttle channel structure 22 b of the second channel structure and then flow along all further channel structures 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, 26 a, 26 b connected in series to finally flow through the axial portion 26 a of the sixth channel structure into the first channel structure 11 (=fluid outlet 102).

So to speak, the fluid meanders through the entire series connection of channel structures and is thereby correspondingly throttled.

Alternatively or additionally, a parallel connection of the channel structures can be realized with the expansion valve 100 according to the invention, as is exemplarily shown in FIGS. 5A to 6B.

The parallel connection is characterized, among other things, by the fact that the first valve element 10 has at least one fourth channel structure 14, and wherein, in the first position of the valve elements 10, 20, the third channel structure 23 a, 23 b of the second valve element 20 and the fourth channel structure 14 of the first valve element 10 are additionally aligned with one another and form a third fluid flow path with a third flow resistance between the fluid inlet 101 and the fluid outlet 102. The amount of the third flow resistance may differ from the amount of the first and/or second flow resistance. This means that the third fluid flow path can provide a third throttle stage.

This means that in the first switch position, the first channel structure 11 of the first valve element 10 and the second channel structure 22 a, 22 b of the second valve element 20 are aligned with one another, and simultaneously, the second channel structure 14 of the first valve element 10 and the third channel structure 23 a, 23 b of the second valve element 20 are aligned with one another.

A parallel connection of the first embodiment (FIGS. 1A to 1D) shall be described below with reference to FIGS. 5A and 5B.

In the embodiment shown here, the first valve element 10 has at least one further channel structure 14. The first valve element 10 even has three further channel structures, namely a seventh channel structure 14, an eighth channel structure 14′ and a ninth channel structure 14″.

The second valve element 20 essentially corresponds to the embodiment described with reference to FIGS. 1A to 1D. The channel structures formed in the second valve element 20, namely a second channel structure 22 a, 22 b, a third channel structure 23 a, 23 b, a fourth channel structure 24 a, 24 b, and a fifth channel structure 25 a, 25 b, flow into a common channel structure 55 leading to the common fluid outlet 102.

The individual channel structures 11, 14, 14′, 14″ of the first valve element 10 can be aligned with the channel structures, and in particular with the axial portions 22 a, 23 a, 24 a, 25 a, of the channel structures in the second valve element 20. Thus, different switch positions are enabled, wherein depending on the switch position, a different number of the four channel structures 11, 14, 14′, 14″ of the first valve element 10 are aligned with the four channel structures 22 a, 23 a, 24 a, 25 a of the second valve element 20.

FIG. 5B exemplarily shows a switch position in which all four channel structures 11, 14, 14′, 14″ of the first valve element 10 are aligned with the four channel structures 22 a, 23 a, 24 a, 25 a of the second valve element 20. The resulting fluid flow is marked by the arrow 123.

The fluid thus flows through all four channel structures 11, 14, 14′, 14″ of the first valve element 10, as well as through all four channel structures 22 a, 23 a, 24 a, 25 a of the second valve element 20 aligned therewith. This is, so to speak, the largest switching stage in which all channel structures are simultaneously active. Accordingly, the flow rate of the fluid can be highest at this switch position, as the fluid can flow through all channel structures simultaneously.

The total flow resistance, however, is again composed of the individual flow resistances of the respectively passed through channel structures. Thereby, the individual channel structures 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, 26 a, 26 b can in addition have different flow areas which are not necessarily constant or geometrically variable over the channel length.

For example, a stop function could be achieved here by turning the first valve element 10 by 180° compared to the switch position shown in FIG. 5B. Thereby, none of the channel structures 11, 14, 14′, 14″ of the first valve element 10 would be aligned with any of the channel structures 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, 26 a, 26 b of the second valve element 20.

Common to all the embodiments described so far is that the expansion valve 100 has exactly one fluid outlet 102 and the second and third channel structures 22 a, 22 b; 23 a, 23 b of the second valve element 20 can be fluidly coupled to this one fluid outlet 102. Even if it is not explicitly shown in the Figures, it would be possible, however, that the expansion valves 100, according to the invention, do not have exactly one, but at least one fluid outlet 102, i.e. the expansion valves 100 can also show a second, third, or any number of fluid outlets 102.

Such a case is exemplarily illustrated in the parallel connection of the second embodiment (FIGS. 2A and 2B) shown in FIGS. 6A and 6B, wherein the first valve element 10 has at least one fourth channel structure 14 and the first and fourth channel structures 11, 14 each form a fluid outlet 102, 102′ of the expansion valve 100.

In the embodiment shown here, the first valve element 10 has at least one further channel structure 14. The first valve element 10 even has three further channel structures, namely a seventh channel structure 14, an eighth channel structure 14′, and a ninth channel structure 14″.

The second valve element 20 essentially corresponds to the embodiment described with reference to FIGS. 2A and 2B. The channel structures formed in the second valve element 20, namely a second channel structure 22 a, 22 b, a third channel structure 23 a, 23 b, a fourth channel structure 24 a, 24 b, and a fifth channel structure 25 a, 25 b, have a radially extending portion 22 b also referred to as a throttle channel structure, 23 b, 24 b, 25 b through which the fluid can flow into the second valve element 20, and an axial portion 22 a, 23 a, 24 a, 25 a which can be aligned with at least one of the channel structures 11, 14, 14′, 14″ arranged in the first valve element 10.

Thus, different switch positions are enabled, wherein, depending on the switch position, a different number of the four channel structures 22 a, 23 a, 24 a, 25 a of the second valve element 20 are aligned with the four channel structures 11, 14, 14′, 14″ of the first valve element 10.

FIG. 6B exemplarily shows the expansion valve 100 in the switch position which is better recognizable in FIG. 6A, in which all four channel structures 22 a, 23 a, 24 a, 25 a of the second valve element 20 are aligned with the four channel structures 11, 14, 14′, 14″ of the first valve element 10. The resulting fluid flow is marked with the arrows 124, 124′, 124″, 124″.

The fluid leaves the expansion valve 100 through all released fluid outlets 11, 14, 14′, 14″, which in turn is shown by the arrows 124′, 124″, 124″′ indicating the fluid flow.

To be more precise, the fluid first flows through the fluid inlet 101 into the expansion valve 100. It is then distributed over all four channel structures 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b in the second valve element 20, which is represented by the arrows 124, 124′, 124″, 124″′. This means that a first portion 124 of the fluid flow enters at the first channel structure 22 a, 22 b, a second portion 124′ of the fluid flow enters at the second channel structure 23 a, 23 b, a third portion 124″ of the fluid flow enters at the third channel structure 24 a, 24 b, and a fourth portion 124″′ of the fluid flow enters at the fourth channel structure 25 a, 25 b.

The fluid thus flows through all four throttle channel structures or radial portions 22 b, 23 b, 24 b, 25 b of the four channel structures of the second valve element 20 into the second valve element 20. Then, the fluid flows into the axial sections 22 a, 23 a, 24 a, 25 a of the channel structures of the second valve element 20, which in the illustrated switch position are all aligned to a respective channel structure 11, 14, 14′, 14″ of the first valve element 10. The fluid leaves the expansion valve 100 through the respective channel structures 11, 14, 14′, 14″ of the first valve element 10, as these simultaneously form the multiple fluid outlets 102, 102′, 102″, 102″′ of the expansion valve.

So to speak, the switching stage shown in FIG. 6B is the largest switching stage, in which all channel structures are active simultaneously. Accordingly, the flow rate of the fluid can be highest at this switch position, as the fluid can flow through all channel structures simultaneously.

The total flow resistance is again composed of the individual flow resistances of the channel structures respectively passed through. Thereby, the individual channel structures 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, 26 a, 26 b can also have different flow areas which are not necessarily constant or geometrically variable over the channel length.

A stop function could, for example, be achieved here by turning the second valve element 20 by 180° compared to the switch position shown in FIG. 6A. Thereby, none of the channel structures 22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, 26 a, 26 b of the second valve element 20 would be aligned with any of the channel structures 11, 14, 14′, 14″ of the first valve element 10.

According to the invention, the individual positions of the valve elements 10, 20 can be switched in discrete stages with the expansion valve 100 proposed here.

In principle, the expansion valve 100 could also have a combination of a parallel connection with a series connection. Such a case is exemplarily shown in the form of a schematic block diagram in FIG. 7.

The fluid flow passing through the expansion valve 100 first passes through a channel structure 22 with a first flow resistance of 71 and then into a parallel connection of channel structures 23, 24, 25 with a second flow resistance of 72, a third flow resistance of 73 and a fourth flow resistance of 74. The flow resistances 71, 72, 73, 74 can be of the same size or different.

The channel structure 22 is connected in series with the parallel connection of the channel structures 23, 24, 25. The total flow resistance is again composed of the individual flow resistances of the channel structures 22, 23, 24, 25 passed through.

The expansion valve 100 can be made of different materials, i.e. the expansion valve 100 can have metal, plastic, glass or ceramic. The individual parts, i.e. the first valve element 10, the second valve element 20 and the cover 30 can be screwed, clamped, glued or welded together.

The channel structures, and in particular the radially extending channel structures 22 b, 23 b, 24 b, 25 b, 26 b referred to as throttle channel structures, can be microchannel structures. These microchannel structures can have flow areas in the range of square millimeters or square micrometers. The microchannel structures can, for example, be introduced into the respective valve element 10, 20 by means of precision milling or produced by injection molding or embossing. It is also conceivable that the microchannel structures are introduced into the respective valve element 10, 20 using etching processes, for example if the respective valve element 10, 20 contains silicon or other materials reactive to etching agents.

The expansion valve 100 according to the invention can, for example, be arranged between two heat exchangers in a refrigeration cycle. Such heat exchangers can be, for example, so-called evaporators or condensers. For example, the expansion valve may be arranged between such an evaporator and a condenser. The expansion valve 100 can also be arranged between at least two evaporators with at least one downstream condenser.

In addition, a household refrigerating device, in particular a refrigerating and/or freezing device with an expansion valve 100 according to the invention is conceivable. This may refer to refrigerating devices and/or freezing devices with a cooling capacity of less than 1000 watts. For example, these can be refrigerators, freezers or fridge-freezer combinations.

In principle, the expansion valve 100 according to the invention can be used in any type of cooling unit, especially in compression cooling units. However, the expansion valve 100 may be used in refrigerating machines with mass flow rates of less than 3 kg/h.

The expansion valve 100 according to the invention may also have means for binding moisture. For example, zeolite can be used as such a moisture-binding agent. Zeolite may be used in the form of bulk material or as sintered material.

The means for binding moisture, for example, can be arranged in the fluid flow direction up-stream of the fluid inlet 101. The means for binding moisture may be arranged between the fluid inlet 101 and the first and second valve elements 10, 20, respectively. For example, the means for binding moisture may be arranged in the recess 31 of the cover 30.

However, the means for binding moisture may also be arranged in one or more of the channel structures 11, 14, 22, 23, 24, 25, 26 of the first and/or second valve element 10, 20, in particular when the means for binding moisture are present in the form of loose bulk material.

Moisture binding agents are advantageous for binding any moisture in the refrigerant and thus for preventing unwanted ice formation elsewhere in the refrigerating cycle.

Furthermore, the expansion valve 100 according to the invention may have at least one particle filter. The particle filter may be arranged in the flow direction downstream the moisture binding agent. The particle filter may filter particles that originate from the agent used to bind moisture, thus, for example zeolite particles.

For the retention of a particle which may be in the fluid flowing through the expansion valve 100, the expansion valve 100 according to the invention may, for example, have a retention element according to another aspect of the invention.

A particle filter as just mentioned is one of several examples of such a retention element. What such retention elements may look like for use with an expansion valve 100 according to the invention shall be described in more detail with reference to FIGS. 11 to 21 d on the basis of the following embodiments.

In general, a retention element may be arranged anywhere in or on the expansion valve 100 along a fluid flow path passing through the expansion valve 100. Several retention elements are also conceivable. Several retention elements can be provided, wherein at least one retention element can be provided per throttle channel structure. Alternatively or additionally, a central retention element can be provided with which at least two throttle channel structures are fluidly coupled. Some embodiments for this purpose shall now be described in more detail below with reference to the Figures.

In the following, embodiments of a retention element that has at least two filter channel structures are first described. The filter channel structures can, for example, be formed in the first valve element 10. Alternatively or additionally, the filter channel structures may be formed in the second valve element 20, or at least in a part 20 a, 20 b of the two-part second valve element 20.

Only to simplify the description of the channel structures, as for example the filter channel structures, throttle channel structures and collector channel structures described below, it is assumed for the embodiments described herein that the channel structures, and in particular the filter channel structures 222 and/or the throttle channel structures 21 b to 27 b, are formed in the first part 20 b of the two-part second valve element 20 shown in FIG. 2A. The following FIGS. 11 and 13 to 17 show a top view of the first part 20 b of the two-part second valve element 20 shown in FIG. 2A. Alternatively or additionally, it is of course generally conceivable, however, that the filter channel structures 222 and/or the throttle channel structures 21 b to 27 b are formed in the second part 20 a of the second valve element 20 and/or in the first valve element 10. In addition, all the channel structures described below, in particular the filter channel structures 222 and the throttle channel structures 21 b to 27 b, can also be configured in the form of a throttle bore. This applies in particular to a possible embodiment of the throttle channel structure 26 b, 27 b described below with the largest cross-section of all throttle channel structures that can provide a free-flow or “open” function. Such a throttle bore may, for example, be an axial bore extending through the first part 20 b and/or the second part 20 a of the second valve element 20 and/or through the first valve element 10. The axial direction 33 refers to the rotation axis of the rotatable valve elements 10, 20 which are exemplarily described below.

Thus, FIG. 11, for example, shows a top view of the first part 20 b of the two-part second valve element 20 shown in FIG. 2A. The individual channel structures 22 a, 22 b; 23 a, 23 b; 24 a, 24 b; 25 a, 25 b can be recognized which are formed along the upper side of the first part 20 b of the two-part second valve element 20 in facing the observer.

Since the first valve element 10 (not shown here) has a first channel structure 11, the channel structures formed in the first part 20 b of the second valve element 20 are referred to as a second channel structure 22 a, 22 b, a third channel structure 23 a, 23 b, a fourth channel structure 24 a, 24 b and a fifth channel structure 25 a, 25 b.

As already described above, the channel structures in this embodiment may each have an axially extending portion 22 a, 23 a, 24 a, 25 a and a radially extending portion 22 b, 23 b, 24 b, 25 b. The radial portions 22 b, 23, 24 b, 25 b contribute the major part to the throttling of a fluid flowing through the channel structures. Therefore, the radial sections are also referred to as throttle channel structures 22 b, 23 b, 24 b, 25 b.

The throttle channel structures 22 b, 23 b, 24 b, 25 b can have different flow resistances, for example due to different cross-sections.

Thus, according an embodiment of the invention, the second channel structure 22 a, 22 b can have a first throttle channel structure 22 b with a certain cross-section of any geometrical shape, e.g. triangular, square, polygonal, trapezoidal, circular, semicircular, etc., and the third channel structure 23 a, 23 b can have a second throttle channel structure 23 b, which also has a certain cross-section of any shape.

The cross-section of the first throttle channel structure 22 b can be the same as the cross-section of the second throttle channel structure 23 b. Alternatively, the respective cross-sections of the first throttle channel structure 22 b and the second throttle channel structure 23 b may, however, deviate from one another.

The throttle channel structures 22 b, 23 b can have different flow resistances. The flow resistance can result, for example, from a length of the throttle channel structure 22 b, 23 b passed through, the cross-section of the throttle channel structure 22 b, 23 b passed through which is not necessarily constant along the channel length, from a change in the cross-section passed through or the channel course, from a geometric cross-sectional shape, from a roughness of the surface of the walls of the throttle channel structure 22 b, 23 b passed through, or from a combination of these parameters. The different flow resistances throttle the flow of the fluid to different degrees. The throttling effect can be adjusted by varying the above parameters.

In addition, the expansion valve according to the invention, or in this embodiment the second valve element 20 shown in FIG. 11, has at least one retention element 200 which is configured to retain a particle 210 present in the fluid flowing through the expansion valve 100.

In the embodiment shown in FIG. 11, even two retention elements 200, 200′ are exemplarily provided for illustrative purposes only. A first retention element 200 is arranged in the area of the first throttle channel structure 22 b. A second retention element 200′ is arranged in the area of the fourth throttle channel structure25 b. However, according to the invention, one retention element 200 is already sufficient.

Each of the two retention elements 200, 200′ shown here has at least two filter channel structures 222 a, 222 b; 225 a, 225 b, each of which is fluidly coupled to at least one throttle channel structure 22 b, 25 b. The first retention element 200 is connected to the first throttle channel structure 22 b, and the second retention element 200′ to the fourth throttle channel structure 25 b and is fluidly coupled.

The filter channel structures 222 a, 222 b; 225 a, 225 b may, for example, be introduced into the second valve element 20 in the same way as the throttle channel structures 22 b, 23 b, 24 b, 25 b, thus, for example, by milling, laser cutting and the like.

The filter channel structures 222 a, 222 b of the first retention element 200 are fluidly coupled with the first throttle channel structure 22 b. This means that a fluid exchange between the respective channel structures 222 a, 222 b; 22 b is possible.

The filter channel structures 225 a, 225 b of the second retention element 200′ are fluidly coupled with the fourth throttle channel structure 25 b. This means that a fluid exchange between the respective channel structures 225 a, 225 b; 25 b is possible.

The filter channel structures 222 a, 222 b; 225 a, 225 b are also led to the edge of the first part 20 b of the second valve element 20 and provide a fluid inlet there. This means that fluid can flow into the respective filter channel structures 222 a, 222 b; 225 a, 225 b. The fluid flowed in then flows along the respective filter channel structure 222 a, 222 b; 225 a, 225 b up to the respective throttle channel structure 22 b, 25 b each of which is fluidly coupled to it.

The filter channel structures 222 a, 222 b; 225 a, 225 b are configured to retain a particle 210. In the embodiment shown in FIG. 11, a particle 210 is clogging one of the two filter channel structures 222 a, 222 b of the first retention element 200 fluidly coupled to the first throttle channel structure 22 b. In addition, a particle 210′ is clogging one of the two filter channel structures 225 a, 225 b of the second retention element 200′ fluidly coupled to the fourth throttle channel structure 25 b.

Such a situation is shown in a magnified view in FIG. 12. FIG. 12 schematically shows a retention element 200 with six filter channel structures 222 a to 222 f, all of which are fluidly coupled to the throttle channel structure 22 b. In this embodiment, the filter channel structures 222 a to 222 f are also arranged in the fluid flow direction upstream the throttle channel structure 22 b. Thus, the filter channel structures 222 a to 222 f can retain a particle 210 before this particle 210 can penetrate into the respective throttle channel structure 22 b and block it.

The individual filter channel structures 222 a to 222 f can all have the same cross-section or, as shown, cross-sections being different from one another.

According to an embodiment of the present invention, the cross-section of the filter channel structures 222 a to 222 f is smaller than or equal to the cross-section of the throttle channel structure 22 b fluidly coupled to it. Thus, the filter channel structures 222 a to 222 f can retain a particle 210 that would be large enough to penetrate and block the respective throttle channel structure 22 b.

The cross-section means at least the cross-section of the fluid inlet surface into the respective channel structure 22 b; 222 a, 222 b. This means the cross-section or opening at the beginning of the channel structure 22 b; 222 a, 222 b through which the fluid enters the respective channel structure 22 b; 222 a, 222 b.

According to an embodiment, at least one filter channel structure 222 a, 222 b and at least one throttle channel structure 22 b may each have an angular cross-section, and at least one side of the angular filter channel structure 222 a, 222 b may be smaller or equal in size to the shortest side of the angular throttle channel structure 22 b.

If, for example, the throttle channel structure 22 b has an angular cross-section with a dimension of 50×40, the filter channel structure 222 a, 222 b could thus have a cross-section with a dimension of 40×40 in order to be able to guarantee the retention or filter function described above. However, the filter channel structure 222 a, 222 b could also have a cross-section with a dimension of 100 x 30 in order to be able to guarantee the retention or filter function described above. As described, at least one side of the angular filter channel structure 222 a, 222 b is therefore smaller or equal in size to the shortest side of the angular throttle channel structure 22 b.

According to another conceivable embodiment, at least one filter channel structure 222 a, 222 b and at least one throttle channel structure 22 b could each have a circular cross-section, wherein the cross-section of the circular filter channel structure 222 a, 222 b is smaller than the cross-section of the round throttle channel structure 22 b, in order to be able to guarantee the retention or filter function described above.

As can additionally be seen in the embodiment shown in FIG. 12, a collector channel structure 230 can be arranged between the filter channel structures 222 a to 222 f and the throttle channel structure 22 b each being fluidly coupled to one another.

This collector channel structure 230 can be fluidly coupled in each case to the filter channel structures 222 a to 222 f and to at least one throttle channel structure 22 b so that a fluid flowing in through at least one filter channel structure 222 a to 222 f is collected in the collector channel structure 230 and passed on into the at least one throttle channel structure 22 b.

The fluid flows into the filter channel structures 222 a to 222 f in the direction of the arrow shown. Since all filter channel structures 222 a to 222 f are fluidly coupled to the collector channel structure 230, the fluid then flows further into said collector channel structure 230 and is collected there. The fluid collected in the collector channel structure 230 then flows further in the direction of the arrow into the respective throttle channel structure22 b which is fluidly coupled to the collector channel structure 230.

Since the sixth filter channel structure 222 f in FIG. 12 is clogged by a particle 210, little or no fluid flows through it, which is why the arrow indicating the fluid flow direction is only shown in dashed lines.

The retention element 200, 200′ shown in FIGS. 11 and 12 can be arranged individually for each channel. This means that a throttle channel structure 22 b, 23 b can each be connected to a retention element 200, 200′ or can be fluidly coupled.

However, embodiments are also conceivable in which a central retention element 200 is provided which is connected to several throttle channel structures or is fluidly coupled. According to such an embodiment, for example, at least two throttle channel structures 22 b, 23 b can be arranged directly on the collector channel structure 230 and fluidly coupled with the collector channel structure 230.

Such an embodiment is shown in FIG. 13. A retention element 200 with several filter channel structures 222 a to 222j is shown here. Two or more, and advantageously all, filter channel structures 222 a to 222j are fluidly coupled to the collector channel structure 230.

The collector channel structure 230 in turn is fluidly coupled to at least two, and advantageously all, 22 b, 23 b, 24 b, 25 b, 26 b throttle channel structures. The retention element 200 is located in the fluid flow direction upstream of the respective throttle channel structures 22 b, 23 b, 24 b, 25 b, 26 b to prevent a particle 210 from penetrating into the valve element 20 and clogging the throttle channel structures 22 b, 23 b, 24 b, 25 b, 26 b.

FIG. 13 also shows that a throttle channel structure 27 b can have a larger cross-section than the other throttle channel structures 22 b, 23 b, 24 b, 25 b and 26 b. The one throttle channel structure 27 b with the largest cross-section of all throttle channel structures 22 b, 23 b, 24 b, 25 b, 26 b here is not fluidly coupled with the collector channel structure 230. Alternatively or additionally, the throttle channel structure 27 b can also be realized by a channel structure in valve element 20 a, for example, by a bore which is realized by continuing the bore 27 a through valve element 20 a.

The reason for this and the functions that can be realized with it (e.g. flushing function, defrost function) will be explained in more detail later.

In any case, this one throttle channel structure 27 b with the largest cross-section of all throttle channel structures 22 b, 23 b, 24 b, 25 b, 26 b can provide an “open” function mentioned introductorily. This one throttle channel structure 27 b with the largest cross-section of all throttle channel structures 22 b, 23 b, 24 b, 25 b, 26 b has almost no throttling, i.e. the fluid flowing through can flow through this one throttle channel structure 27 almost unhindered or unthrottled.

Another embodiment is shown in FIG. 14. As can be recognized here, a connecting channel structure segment V_(a) can be arranged between at least one throttle channel structure 25 b (V_(b)) and the collector channel structure 230, which connects these at least one throttle channel structure 25 b (V_(b)) and the collector channel structure 230 to one another and couples them fluidly to one another.

In this embodiment, a central retention element 200 is also provided, wherein the central retention element 200 has several filter channel structures 222 a to 222e which lead into a collector channel structure 230.

According to the embodiment shown in FIG. 14, at least one second throttle channel structure 24 b (IV_(b)) is also connected to the connecting channel structure segment V_(a) and fluidly coupled by means of another channel structure segment IV_(a .)

The connecting channel structure segment V_(a) which connects the collector channel structure 230 with the individual throttle channel structures 21 b to 25 b (I_(b) to V_(b)), may cause the fluid flowing through to be throttled. The other channel structure segments I_(a) to IV_(a) may also cause a throttling of the fluid flowing through them.

It may also be conceivable in this embodiment that the throttle channel structure with the largest cross-section of all throttle channel structures I_(b) to V_(b) is not fluidly coupled with the collector channel structure 230.

In contrast, an alternative embodiment is shown in FIG. 15. Here, the throttle channel structure 26 b with the largest cross-section of all throttle channel structures 22 b, 23 b, 24 b, 25 b, 26 b cannot only be fluidly coupled with the collector channel structure 230, but can also form the collector channel structure 230 itself at the same time, wherein the filter channel structures 222 a to 222 u lead into this collector channel structure 230.

In this embodiment, the collector channel structure 230 thus is directly connected to and fluidly coupled with the throttle channel structure 26 b with the largest cross-section of all throttle channel structures 22 b, 23 b, 24 b, 25 b, 26 b. The collector channel structure 230 and the throttle channel structure 26 b thereby may have the same cross-section.

According to the invention, at least two filter channel structures 222 a, 222 b and at least two throttle channel structures 22 b, 23 b are connected directly to the throttle channel structure 26 b, which simultaneously also forms the collector channel structure 230, and are fluidly coupled. In the present embodiment, even all filter channel structures 222 a to 222 u and all throttle channel structures 22 b, 23 b, 24 b, 25 b are connected directly to the throttle channel structure 26 b, which simultaneously also forms the collector channel structure 230, and are fluidly coupled.

If, as shown, a particle 210 clogs a filter channel structure 222 r, then the fluid can flow through all other unclogged filter channel structures 222 a to 222 u into the throttle channel structure 26 b or the collector channel structure 230 and from there flow further to the respective throttle channel structure 22 b, 23 b, 24 b, 25 b, 26 b.

In the embodiments described so far, the collector channel structure 230 was formed in an arc in the second valve element 20. As shown in FIG. 15, the collector channel structure 230 has a radius R_(s) that is smaller than the radius R_(v) of the second valve element 20.

In addition, the filter channel structures 222 a to 222 u, which are fluidly coupled with the collector channel structure 230, can be arranged radially outwards starting from the collector channel structure 230, as shown in FIGS. 13 and 15, for example. Alternatively or additionally, the filter channel structures 222 a to 222 u can also be arranged axially outwards starting from the collector channel structure 230, for example, in the form of axial bores leading into the collector channel structure 230.

At the same time, the filter channel structures 222 a to 222 u in the second valve element 20 can define an opening to the environment through which the fluid can flow into the respective filter channel structure 222 a to 222 u. From there, the fluid flows into the collector channel structure 230 and from there, again, into the respective throttle channel structures 22 b, 23 b, 24 b, 25 b, 26 b.

In the embodiments described so far, the throttle channel structures 22 b to 27 b were all arranged in the fluid flow direction downstream of the filter channel structures 222 a to 222 u, i.e. the fluid flows first into the filter channel structures 222 a to 222 u and then into the throttle channel structures 22 b to 27 b.

FIG. 16 shows a further embodiment according to which the throttle channel structure 26 b with the largest cross-section of all throttle channel structures 22 b, 23 b, 24 b, 25 b, 26 b is connected to the filter channel structures 222 a to 222 g and is fluidly coupled, wherein said one throttle channel structure 26 b is arranged upstream of the filter channel structures 222 a to 222 g in the fluid flow direction. Alternatively or additionally, the filter channel structures 222 a to 222 g can also be fluidly coupled with a channel structure in valve element 20 a, for example, a bore, which is realized by continuing the bore 26 a through valve element 20 a.

This means that the fluid first flows into the throttle channel structure 26 b with the largest cross-section, before flowing to the filter channel structures 222 a to 222 g and from there further to the individual remaining throttle channel structures 21 b, 22 b, 23 b, 24 b, 25 b.

This has the advantage that a particle 210 that clogs one or more of the filter channel structures 222 a to 222 g can be carried away directly by the fluid flow within the throttle channel structure 26 b with the largest diameter and flushed away by the blocked filter channel structure 222 a to 222 g.

A particle 210 flushed away is conveyed through the channel structure 26 a arranged on the fluid outlet side, e.g. axially extending, to the fluid outlet 102 and thus out of the expansion valve 100.

FIG. 17 shows another embodiment of an expansion valve 100 according to the invention. In the Figure at the top right side, the first part 20 b of the two-part second valve element 20 is shown schematically in top view. In the Figure at the top left side, a side view of the first part 20 b of the two-part second valve element 20 is shown. In the Figure at the bottom right side, the second part 20 a of the two-part second valve element 20 is schematically shown in top view. In the Figure at the bottom left side, the second part 20 a of the two-part second valve element 20 is shown in a side view.

According to this embodiment shown in FIG. 17, the expansion valve 100 has a bypass channel structure 223. For example, the bypass channel structure 223 may be formed in the second part 20 a of the second two-part valve element 20, advantageously on the side facing the first part 20 b. The bypass channel structure 223, for example, can also be formed in the first valve element 10.

The bypass channel structure 223 forms a bypass in the fluid flow path for one or more throttle channel structures 21 b, 22 b, 23 b. This means that the bypass channel structure 223 allows fluid to flow through the bypass if, for example, a throttle channel structure 21 b, 22 b, 23 b is clogged by a particle 210 or the like.

In order to guarantee this function, the bypass channel structure 223 can be fluidly coupled to at least one fluid inlet portion 224 of at least one throttle channel structure 21 b in the embodinvent shown here so that, in the case of fluid coupling of the bypass channel structure 223 to this at least one throttle channel structure 21 b, a particle 210 adhering to this fluid inlet portion 224 can be discharged through the bypass channel structure 223. The fluid inlet portion 224 is the portion of the throttle channel structure 21 b through which the fluid flows into the throttle channel structure 21 b.

In general, the fluid inlet portion 224 of a throttle channel structure 21 b, 22 b, 23 b thus is the portion that is open to the environment and allows the fluid to enter the throttle channel structure 21 b, 22 b, 23 b. So to speak, it is the opening through which the fluid enters the respective throttle channel structure 21 b, 22 b, 23 b.

As shown schematically in FIG. 17, the bypass channel structure 223 has a larger cross-section than the throttle channel structures 21 b, 22 b, 23 b.

The particle 210 shown here has clogged the fluid inlet portion 224 of the throttle channel structure 21 b. To remove the particle 210, the bypass channel structure 223 is arranged opposite the clogged throttle channel structure 21 b such that the bypass channel structure 223 at least lies opposite the clogged fluid inlet portion 224 of the throttle channel structure 21 b.

The bypass channel structure 223 thus forms a fluid flow path 225 from the fluid inlet portion 224 of the clogged throttle channel structure 21 b, along the bypass channel structure 223, to an end 226 of the bypass channel structure 223. Said end 226 of the bypass channel structure 223 may, for example, be an opening to the environment through which the particle 210 carried away can be flushed out or removed.

The end 226 of the bypass channel structure 223 can also lead into the fluid outlet 102 of the expansion valve 100 to convey the particle 210 carried away out of the expansion valve 100.

In the example shown in FIG. 17, the bypass channel structure 223 is fluidly coupled to a fluid outlet portion 227 of at least one throttle channel structure 21 b for this purpose. The fluid outlet portion 227 of the respective throttle channel structure 21 b, 22 b, 23 b can be, for example, the axially extending channel structure portion 21 a, 22 a, 23 a of the respective channel structure 21 a, 21 b ; 22 a, 22 b; 23 a, 23 b. Since this fluid outlet portion 227 is fluidly coupled to the fluid outlet 102 of the expansion valve 100, the bypass channel structure 223 can direct the fluid in this embodiment directly to the fluid outlet 102 of the expansion valve 100. A particle 210 carried away is thus flushed out through the fluid outlet 102.

The throttle channel structure 21 b exemplarily mentioned here can thus be coupled fluidly to the bypass channel structure 223 on the inlet side, i.e. at its fluid inlet portion 224, and optionally also on the outlet side, i.e. at its fluid outlet portion 227.

In other words, the bypass channel structure 223 could overlap at least at the fluid inlet portion 224 of a throttle channel structure 21 b with the same fluid inlet portion 224. Alternatively or additionally, the bypass channel structure 223 can also overlap at least at the fluid outlet portion 227 of a throttle channel structure 21 b with this same fluid outlet portion 227.

In the event that the bypass channel structure 223 overlaps with the throttle channel structure 21 b over the entire length, this corresponds to a temporary increase in the effective cross-section of the respective throttle channel structure 21 b.

In order to improve the removal of a particle 210, the at least one throttle channel structure 21 b may optionally at least in sections have a shape widening towards the bypass channel structure 223. For example, at the top left side, FIG. 17 shows a magnified representation of the throttle channel structure 21 b.

It can be recognized that the throttle channel structure 21 b has a trapezoidal shape which widens towards the bypass channel structure 223. The two parts 20 a, 20 b of the two-part second valve element 20 are placed on top of each other as indicated by the arrow 170. Thus, the bypass channel structure 223 and the throttle channel structure 21 b are arranged opposite each other and the throttle channel structure 21 b widens towards the bypass channel structure 223.

Alternatively or additionally it would be conceivable that the expansion valve 100 has means 240 (FIG. 15) for releasing and/or removing a particle adhering to the retention element 200, wherein the means 240 for releasing and/or removing a particle has a mechanical stripping device 241, which can be brought into contact with the retention element 200 and can be moved relative to the retention element 200, and wherein the stripping device 241 is adapted to mechanically remove a particle 210 adhering to the retention element 200 when moving the retention element 200 relative to the stripping device 241.

Such an embodiment is shown in FIG. 15. The means 240 for releasing and/or removing a particle here has a mechanical stripping device 241, which is similar in function to a broom.

The stripping device 241 is here in contact and stationary with the circumference of the first part 20 b of the two-part valve element 20. When the valve element 20 moves past the stripping device 241, a particle 210 adhering to the valve element 20 is stripped off the valve element 20 by the stripping device 241.

Up to now, the retention element 200 has been exemplarily described in the form of the filter channel structures 222. In principle, however, it is of course conceivable that the retention element 200 has a perforated plate and/or sintered material and/or a fabric structure and/or a mesh structure and/or an open-pored sponge structure and/or loose bulk material and/or water-binding material.

Irrespective of the shape in which the retention element 200 is formed, it can provide a fixed flow resistance for the fluid flow passing through the retention element 200. This means that the retention element 200 itself can already provide a throttling function. The amount of this flow resistance, for example, can be at most as large as is used for the smallest throttle stage.

According to an embodiment, the retention element 200 may be configured to throttle the fluid flow through the retention element 200 by 10% or less, advantageously 20% or less, and more advantageously by 30% or less. This means that the retention element 200 offers a fixed throttling, for example 30% or less, in relation to the fluid flow upstream and downstream of the retention element 200.

However, a retention element 200 can also, for example, throttle the fluid flow almost 100% upstream of each throttle channel structure 21 b, 22 b, 23 b, wherein the respective throttle channel structure 21 b, 22 b, 23 b would not have to provide any further throttling.

Alternatively or additionally, the retention element 200 may have means for reducing the flow velocity of a fluid stream flowing along one of the fluid flow paths so that a settling zone is formed in the respective fluid flow path in which penetrated particles can settle.

Such a means for reducing the flow velocity may have at least one baffle wall and/or an extension of the installation space and/or a portion with a cross-section enlarged relative to the throttle channel structure 21 b, 22 b, 23 b.

FIG. 18, for example, shows an example of a retention element 200 that has such a means 250 to reduce the flow velocity. In this embodiment, the means 250 for reducing the flow velocity has an extension of installation space 255 or a portion with an enlarged cross-section compared to the throttle channel structure 21 b. When the fluid flows into this extension of installation space 255, the flow velocity of the fluid is reduced. The flow velocity at the end of the extension of installation space 255 may have dropped to such an extent that a settling zone 252 for the particles 210 is formed there.

In the extension of installation space 255, baffle plates 251 may additionally be arranged. Here, too, settling zones 253 can form in which particles 210 can settle. The baffle plates 251 can also be arranged in a throttle channel structure 21 b to 27 b or in a filter channel structure 222 a to 222 u, i.e. the combination of the extension of installation space 255 with the baffle plates 251 is optional.

In the embodiment shown in FIG. 18, the retention element 200 has a filter channel structure 222 a, 222 b described above in addition to the means 250 for reducing the flow velocity.

However, it is also conceivable that the retention element 200 has only the means 250 for reducing the flow velocity, i.e. without combination with an additional filter channel structure 222 a, 222 b.

In the embodiment shown in FIG. 18, the filter channel structures 222 a, 222 b are arranged in the fluid flow direction between the means 250 for reducing the flow velocity and the respective throttle channel structure 21 b.

The fluid flow direction resulting in this embodiment of a retention element is indicated by the arrow 258. The fluid thus first flows into the extension of installation space 250. Insofar as aforementioned baffle plates 251 are present, the fluid flows past these baffle plates 251, wherein possibly settling zones 253 may form for particles 210 in the area of these baffle plates 251.

The fluid then flows further into the filter channel structures 222 a, 222 b, which are directly connected and fluidly coupled to it. By means of these filter channel structures 222 a, 222 b, particles 210 can also be retained in the manner described above. The fluid then flows into the respective throttle channel structure 21 b connected and fluidly coupled to it.

It would also be conceivable that a collector channel structure 230 not explicitly shown here is arranged between the filter channel structures 222 a, 222 b and the throttle channel structure 21 b.

The means 250 for reducing the flow velocity may be fluidly coupled to at least one throttle channel structure 21 b in order to keep particles 210 away from this throttle channel structure 21 b.

As mentioned above, a settling zone 252 can form in the means 250 for reducing the flow velocity. It would be conceivable here that the settling zone 252 is arranged such that a particle which adheres to the retention element 200 when the fluid flow is present settles in the settling zone 252 when the fluid flow decreases due to gravity. Such a case would be conceivable, for example, if FIG. 18 were turned by 180° and the fluid would flow against gravity, for example essentially from bottom to top.

Thus, this function could be realized, for example, in general by flowing against the retention element 200 from the bottom (i.e. contrary to gravity), wherein a particle 210 could accumulate at the lower side of the retention element 200 which is flowed due to the force exerted by the flow. Of course, this also applies to a retention element 200 which, for example, only has the filter channel structures 222 a, 222 b, but not the means 250 for reducing the flow velocity.

As soon as the flow decreases or is no longer present, e.g. as a result of switching off the expansion valve 100, the particle 210 would no longer be flowed and thus due to gravity fall into a settling zone 252 arranged thereunder.

The embodiments described so far for retention elements 200 according to the invention all serve the purpose of preventing a particle 210 in the fluid from penetrating into a throttling channel structure 21 b.

The present invention, however, also offers possibilities to remove particles 210 that have already penetrated the expansion valve 100, for example, by flushing the expansion valve 100. Such flushing functions may be provided by the means described below.

Thus, for example, the two valve elements 10 and 20 can be lifted off from one another. As shown in FIG. 19A, for example, at least one of the two valve elements 10, 20 may have a structure 261, 262 which, upon movement, e.g. upon a rotation, of the two valve elements 10, 20 relative to one another, causes that the two valve elements 10, 20 lift off from one another and thereby form a fluid flow path through the fluid past the throttle channel structures 21 b to the fluid outlet 102.

The example illustrated here shows the first valve element 10 and the first part 20 b of the two-part second valve element 20 including a throttle channel structure 21 b formed in the first part 20 b. The first valve element 10 has an elevation 261. The second valve element 20 has a protruding portion 262.

As can be seen in FIG. 19B, upon a rotation of the two valve elements 10, 20 relative to one another, the protruding portion 262 runs onto the elevation 261. As a result, the two valve elements 10, 20 are lifted off from one another in axial direction 33 (FIG. 19B).

As shown in FIG. 19B, a gap 259 is formed between the two valve elements 10, 20. This gap 259 provides a fluid flow path which, while bypassing the throttle channel structures 21 b, leads directly into the channel structure 11 of the first valve element 10 and thus directly to the fluid outlet 102. A particle 210 can thus be led directly to the fluid outlet 102 without this particle 210 first having to pass through the throttle channel structures 21 b.

Alternatively or additionally, for example, the throttle channel structures 21 b, 22 b, 23 b, 24 b, 25 b, 26 b and/or the filter channel structures 222 a to 222 u can be configured such that their cross-section can be temporarily enlarged.

A particle 210 that has become entangled in a channel structure can thus be removed. If, for example, a particle 210 clogs a throttle channel structure 21 b, 22 b, 23 b, 24 b, 25 b, 26, the first and second parts 20 a, 20 b of the second two-part valve element 20 can be lifted off from one another in order to at least temporarily enlarge the cross-section of the clogged throttle channel structure or of all throttle channel structures, as shall be explained with reference to FIG. 19C.

For example, the first part 20 b and/or the second part 20 a of the second two-part valve element 20 may have a structure 261, 262 similar to that of FIG. 19A but not shown here in more detail which, upon a movement of the second two-part valve element 20, for example upon a rotation, relative to the first valve element 10 and the housing 30 or upon a movement of the two parts 20 a, 20 b relative to one another, causes the two parts 20 a, 20 b to lift off from one another.

Thus, for example, the illustration on the left of FIG. 19C shows an expansion valve 100 that has essentially the same structure as the expansion valve 100 shown in FIG. 2A. This means that the expansion valve 100 has a first valve element 10 and a second valve element 20. The second valve element 20 is made of two parts and has a first part 20 b and a second part 20 a.

In addition, a housing 30 is provided which has a fluid inlet 101 through which fluid can flow into the interior of the housing 30. In FIG. 19C, the fluid inlet 101 is arranged on the upper side of the housing 30. As an example only, an optional second fluid inlet 101′ is marked here which can be arranged in a side wall of the housing 30.

The illustration on the right of FIG. 19C shows a state in which the first part 20 b is lifted off from the second part 20 a of the second two-part valve element 20 in axial direction 33. Thereby, a flushing function can be realized for the throttle channel structure 21 b through the channel structure 21 a to the fluid outlet 102.

It would also be conceivable here, for example, that the second part 20 a of the second valve element 20 is lifted off from the first part 20 b of the second valve element 20 to such an extent that the second part 20 a with the inner side of the housing 30 comes into contact with the second part 20 a. The second part 20 a could thereby close the above mentioned fluid inlets 101, 101′, as shown in the illustration on the right of FIG. 19C.

This means that a new sealing surface is created here at the fluid inlet 101, 101′. This results in a widening of the cross section to allow a particle 210 to flow off and, if applicable, an improved sealing surface can be created for the stop function, since the second part 20 a of the second valve element 20 in this case moves perpendicularly to this new sealing surface and not along said sealing surface.

If, for example, the embodiment shown in FIG. 10 is considered, it would also be conceivable alternatively that the first valve element 10 is lifted off so far from the second valve element 20 that the first valve element 10 comes into contact with the inner side of the housing 30. The first valve element 10 could close the above mentioned fluid inlets 101, 101′, analogously to the variant shown in the illustration on the right of FIG. 19C.

FIGS. 20A and 20B show another possibility to flush particles 210 out of the expansion valve 100.

These two embodiments are characterized in that one of the two valve elements 10, 20 has a channel structure 270, which causes a reversal of the flow direction of the fluid flow passing through this other valve element 10, 20 in the other of the two valve elements 10, 20.

Thus, FIG. 20A, for example, shows an embodiment in which only the right side, i.e. to the right of the axis 41, is to be considered first. A throttle channel structure 21 b is formed in the second valve element 20. In the first valve element 10, a first channel structure 269 is formed through which the fluid can flow in and flow into the throttle channel structure 21 b. This results in the flow direction of the fluid indicated by the arrows.

The illustration to the left of the axis 41 shows a second position of the valve elements 10, 20.

Here, for example, the second valve element 20 would be turned by 180° relative to the first valve element 10.

As can be seen, the throttle channel structure 21 b is now arranged opposite another channel structure 270 formed in the first valve element 10. Although this is still the same throttle channel structure 21 b, it is, however, in a different position, which is why this throttle channel structure is provided in this case with the reference sign 21 b′.

The channel structure 270 formed in the first valve element 10 causes the fluid flow direction in the throttle channel structure 21 b′ to be reversed, which is indicated by the arrows. Thus, a particle 210 which may have settled in the throttle channel structure 21 b, 21 b′, can be flushed out in the opposite direction and through the expansion valve 100.

FIG. 20B shows another embodiment for reversal of the flow direction. In a first position (to the right of the axis 41), the fluid flows through the first channel structure 269 a into the throttle channel structure 21 b and from there into the second channel structure 269 b. The arrangement of the channel structures 269 a, 269 b relative to the throttle channel structure 21 b results in the flow direction indicated by the arrows. The fluid here thus flows from the inside to the outside, i.e. away from the axis 41.

To the left of the axis 41, a second switch position is then drawn, wherein the throttle channel structure is again provided with the reference sign 21 b′. In this second position (to the left of the axis 41) the fluid flows through the first channel structure 270 a into the throttle channel structure 21 b′ and from there into the second channel structure 270 b.

The arrangement of the channel structures 270 a, 270 b relative to the throttle channel structure 21 b′ results in the flow direction indicated by the arrows. The fluid here thus flows from the outside to the inside, i.e. towards the axis 41. Thus, a particle which may have settled in the throttle channel structure 21 b, 21 b′ can be flushed out in the opposite direction and through the expansion valve 100.

As already mentioned several times, the expansion valve 100 according to the invention can be brought into several switch positions. This can be achieved, among other things, by the fact that the first valve element 10 can be moved, in particular rotated, in relation to the second valve element 20.

As already mentioned at the very beginning of this disclosure, the expansion valve 100 according to the invention can, for example, have a switch position in which the fluid passing through is almost not throttled, i.e. the fluid flows almost unhindered through the expansion valve 100. This switch position can therefore be described as an “open” function or as a free-flow switch position.

The expansion valve 100 can also have a further switch position in which the flow of the fluid is almost completely throttled or blocked (i.e. with the exception of possible leakages). This switch position can therefore also be referred to as the “stop” position or blocking switch position.

The throttle channel structures 21 b, 22 b, 23 b, 24 b, 25 b, 26 b form fluid flow paths with different throttle stages between the free-flow switch position and the blocking switch position. The amount of the throttling effect can be determined, for example, by the cross-section of the respective throttle channel structure 21 b, 22 b, 23 b, 24 b, 25 b, 26 b. Since every throttle channel structure 21 b, 22 b, 23 b, 24 b, 25 b, 26 b thus enables a flow of the fluid, these switch positions are also referred to as flow switch positions.

Thereby, the throttle channel structure 26 b with the largest cross-section of all throttle channel structures 21 b, 22 b, 23 b, 24 b, 25 b, 26 b can enable an almost unhindered flow or a free flow, which is why this switch position accordingly can also realize a free flow switch position.

According to a conceivable embodiment of the present invention, the expansion valve 100 can thus be brought into several positions, wherein in a free-flow switch position, the throttle channel structure 26 b with the largest cross-section of all throttle channel structures 21 b, 22 b, 23 b, 24 b, 25 b, 26 b forms the fluid flow path, and wherein in a blocking switch position a fluid flow path is blocked.

The individual switch positions can be achieved by the fact that the first valve element 10 relative to the second valve element 20 is movable, and in particular rotatable.

In summary, the expansion valve 100 according to a conceivable embodiment of the invention may be brought into a blocking switch position and into a plurality of flow switch positions by means of the relative movement between the first and second valve elements 10, 20, wherein the expansion valve 100 in each flow switch position provides a fluid flow path having respectively a different flow resistance between the fluid inlet 101 and the fluid outlet 102, and wherein in the blocking switch position, a fluid flow path between the fluid inlet 101 and the fluid outlet 102 is blocked.

One aspect of the present invention is that the expansion valve 100 can be brought into the different switch positions as energy-saving and efficient as possible. In the following, FIGS. 21A to 21D shall be referred to. These figures each show a diagram illustrating a flow rate (y-axis) as a function of the switch position. The distances between the individual switch positions are represented by the number of steps (x-axis) that a stepper motor would have to travel to reach the respective switch positions.

FIG. 21A, for example, shows a diagram of an expansion valve 100 with linearly increasing flow or linearly decreasing throttling. The origin of the diagram starts at the zero position of the expansion valve 100, at which no flow takes place. The expansion valve 100 is thus in a blocking switch position 380, which serves here as reference or starting position.

Starting from this blocking switch position 380, a first flow switch position 381 is reached after ten steps, for example. In this first flow switch position 381, the expansion valve 100 has a first flow resistance or a first throttle stage.

After a further ten steps, thus, after a total of twenty steps, a second flow switch position 382 providing a second throttle stage is reached, wherein this second throttle stage is smaller than the first throttle stage. In the second flow switch position 382, the expansion valve 100 therefore has a lower flow resistance than in the first flow switch position 381.

After a further ten steps, thus, after a total of thirty steps, a third flow switch position 383 providing a third throttle stage is reached, wherein this third throttle stage is smaller than the first and second throttle stages. In the third flow switch position 383, the expansion valve 100 therefore has a lower flow resistance than in the first and second switch positions 381, 382.

This can be continued until a free-flow switch position 386 is reached which allows an “open” function.

The diagram shown in FIG. 21A thus represents an expansion valve 100 with a linearly increasing flow rate or with a linearly decreasing flow resistance and thus a linearly decreasing throttling rate.

In accordance with the embodiment shown in FIG. 21A, the individual flow switch positions 381 to 386, starting from the blocking switch position 380, can thus be arranged in descending order with respect to their respective flow resistance so that with a relative movement of the two valve elements 10, 20 from one switch position 381 to the next switch position 382, the respective flow resistance decreases.

FIG. 21B, on the other hand, shows exactly the opposite, namely a diagram showing an expansion valve 100 with a linearly decreasing flow rate or with a linearly increasing flow resistance and thus a linearly increasing throttling rate.

In accordance with the embodiment shown in FIG. 21B, the individual flow switch positions 381 to 386, starting from the blocking switch position 380, can thus be arranged in ascending order relative to their respective flow resistance so that with a relative movement of the two valve elements 10, 20 from a switch position 381 to the next switch position 382, the respective flow resistance increases.

FIG. 21C shows a diagram representing an expansion valve 100 in which the individual switching stages 380 to 386 are arranged in an arbitrary order.

FIG. 21D shows a diagram representing an expansion valve 100 in which the switching stages are arranged according to their frequency of use, wherein the number 1 represents the most frequent and the number 6 the least frequent.

For example, the blocking switch position 380 (stop position) is provided between two stops of the expansion valve 100. In other words, the expansion valve 100 can be rotated both to the left and to the right from this blocking switch position 380.

It would now be conceivable, for example, that the flow switch position 381 is used more frequently than the flow switch position 384. Starting from the blocking switch position 380, the flow switch position 381 can therefore be arranged closer to the blocking switch position 380 than the less frequently used flow switch position 384.

For example, the flow switch position 381 can be approached with ten steps starting from the blocking switch position 380, while the flow switch position 384 can be approached with a total of twenty steps starting from the blocking switch position 380. The flow switch position 381 is used more frequently than the flow switch position 384.

It would also be conceivable that the flow switch position 382 is also frequently used. For example, the flow switch position 382 may be used less frequently than the flow switch position 381, but more frequently than the flow switch position 384.

Starting from the blocking switch position 380, said flow switch position 382 can be approached with ten steps each, just as the above mentioned and frequently used flow switch position 381, but in the opposite direction.

In this arrangement of the flow switch positions 381, 382 shown in FIG. 21D, the advantage over the linear arrangements (FIGS. 21A, 21B) is that both the flow switch position 381 and the flow switch position 382 can be approached with only ten steps, starting from the blocking switch position 380. Wth the linear arrangement, on the contrary, to reach a second flow switch position 382, twenty steps would have to be approached, starting from the blocking switch position 380.

As mentioned introductorily, the individual flow switch positions 381 to 386 are arranged here depending on their frequency of use.

According to the embodiment of the present invention shown in FIG. 21D, the individual flow switch positions 381 to 386, starting from the blocking switch position 380, can thus be arranged in a sequence relative to their respective flow resistance, wherein this sequence depends on how often the respective switch position 381 to 386 is used during operation.

The individual switch positions are achieved by the relative movement of the two valve elements 10, 20 relative to one another. Of course, the relative movement of the two valve elements 10, 20 does not have to be carried out with a stepper motor. The diagrams described above in FIGS. 21A to 21D have only been exemplarily described by means of the number of steps of a stepper motor to be driven. The diagrams primarily serve to show the individual switch positions which of course can be independent of the presence of a stepper motor.

In more general terms, in order to approach the frequently used switch positions as efficiently as possible, the distance between two switch positions can simply be shortened accordingly. According to an embodiment of the present invention, the distance to be covered in the relative movement of the two valve elements 10, 20 to reach a certain flow switch position 381 to 386 for a frequently used flow switch position can therefore be shorter than for a less frequently used flow switch position 381 to 386, starting from the blocking switch position 380.

Frequently used switch positions are those which are used in normal operation, e.g. several times a day.

Another embodiment of the present invention provides that the expansion valve 100 has a blocking switch position 380 between two flow switch positions 381 to 386. Thus, a separate blocking switch position 380 can be provided between each flow switch position 381 to 386.

This saves turning back the valve elements 10, 20 to a central blocking switch position 380. This is an advantage in terms of energy savings, since a stepper motor, for example, has to travel considerably fewer steps to reach a blocking switch position 380.

Due to the blocking switch position 380 (stop position), in particular in combination with the above mentioned free-flow switch position 386 (“open” function), results in further advantages for the expansion valve 100 according to the invention. Thus, for example, a defrost function can be provided.

Thus, according to a conceivable embodiment of the invention, for example, the expansion valve 100 may be configured to provide a defrost function by first placing the expansion valve 100 in the blocking switch position 380, wherein the pressurized fluid is heated. The expansion valve 100 can then be brought directly into the free-flow switch position 386, wherein an evaporator fluidly coupled with the expansion valve 100 is flooded with the heated fluid.

Aspects of the present invention also provide a refrigerator and/or freezer with an expansion valve 100 described above.

According to an embodiment, such a refrigerating and/or freezing device may have a compressor, an evaporator and a control device. Thereby, the control device may be configured to determine at least one parameter including an air temperature and/or an evaporator temperature and/or a compressor running time and/or a compressor switching stage and/or an ambient temperature and/or a pressure.

Based on one or more of these parameters (e.g. air temperature and/or an evaporator temperature and/or a compressor running time and/or a compressor switching stage and/or an ambient temperature and/or a pressure), the control device may further be configured to activate a flushing function in which the expansion valve 100 is adjusted such that the fluid flows through that throttle channel structure having the largest cross-section of all the throttle channel structures 26 b. This means that the control device brings the expansion valve 100 into a free-flow switch position 386.

In order to explain the effect of said flushing function, it is again referred to FIG. 16. If the retention element 200 or the filter channel structures 222 a to 222 g are configured such that the throttle channel structure 26 b used for the “open” position passes the retention element 200, the fluid (e.g. refrigerant) flows past the retention element 200 after switching to the free-flow switch position 386. Particles 210 can thus be carried away, passed through the expansion valve 100 and the retention element 200 thus can be flushed out again, since the throttle channel structure 26 b provides 386 considerably larger channel cross-sections for throttling than the other throttle channel structures 21 b, 22 b, 23 b, 24 b, 25 b for the “open function”.

It would further be conceivable that, as with the defrost function mentioned above, that when the expansion valve 100 is closed, pressure is built up specifically via the compressor and then suddenly reduced via the “open” position 26 b.

Such a flushing function can be performed automatically at regular intervals. Alternatively, the following scheme can also be used to identify if and when such a flushing function shall be applied:

-   -   1) The unit notices, e.g. on the basis of air temperature,         evaporator temperature, compressor running time, compressor         switching stage, ambient temperature, pressure and/or         combination of the parameters, that cooling capacity is lacking.     -   2) Flushing function is activated.     -   3) If the flushing function is successful, normal further         operation.     -   4) If the flushing function is not successful, emergency         function, i.e. other e.g. next higher channel is used.

According to such an embodiment of the invention, the control device may, for example, be further configured to activate the flushing function at regular intervals or to carry out a set-point/actual value comparison of one or more of the aforementioned parameters (air temperature and/or evaporator temperature and/or compressor running time and/or compressor switching stage and/or ambient temperature and/or pressure), wherein the control device, in the event of a positive result of the setpoint/actual value comparison, puts the refrigerator and/or freezer into a normal operating state, and the control device, in the event of a negative result of the setpoint/actual value comparison, switches the refrigerator and/or freezer into an emergency running function, in which the expansion valve 100 is brought into a flow switch position which has a throttle channel structure 21 b, 22 b, 23 b, 24 b, 25 b with a smaller cross-section.

In the following, the expansion valve 100 according to the invention as well as conceivable concepts of the invention are described again in other words:

One subject matter of the invention is a valve 100 which can throttle a fluid flow from almost 100% maximum flow to almost 0% flow in discrete stages. The primary application is seen as micro expansion valve 100 in refrigeration cycles in the lower refrigeration capacity range, since it solves the problem of refrigerant dosing at low mass flows mentioned introductorily.

Two implementation forms A and B are again described in more detail with reference to the Figures. A possible drive for operation is shown in FIGS. 9 and 10. For rotating the rotary disk (first valve element 10 or second valve element 20), for example, a stepper motor can be used.

Implementation Form A

In implementation form A (FIGS. 1A to 1D), N inlets (axial portions 22 a, 23 a, 24 a, 25 a) to individual microfluidic channel structures (radial portions or throttle channel structures 22 b, 23 b, 24 b, 25 b) are located in the here two-part valve seat (second valve element 20 with first part 20 a and second part 20 b), the respective outlets of which in turn are combined into a single common main outlet (fluid outlet 102).

On the valve seat 20 there is a rotatable disk (first valve element 10). By rotary positioning of the distributor (first channel structure 11) in the rotary disk 10, the flow through the valve 100 can be completely blocked on the one hand or on the other hand one of the microfluidic channel structures 22 b, 23 b, 24 b, 25 b can be released in each case. Since the channel structures 22 b, 23 b, 24 b, 25 b differ geometrically and therefore have a different flow resistance, each channel structure 22 b, 23 b, 24 b, 25 b represents a specific throttle stage. These channel structures 22 b, 23 b, 24 b, 25 b can therefore also be described as throttle channel structures. A structure in the valve seat 20 can also be configured such that no significant throttling takes place (passage).

Implementation Form B

In implementation form B (FIGS. 2A and 2B), N inlets (radial portions or throttle channel structures 22 b, 23 b, 24 b, 25 b) to individual microfluidic channel structures (radial portions or throttle channel structures 22 b, 23 b, 24 b, 25 b) are located in the here two-part rotary disk (second valve element 20 with first part 20 a and second part 20 b), the respective outlets of which (axial portions 22 a, 23 a, 24 a, 25 a) are located on the sliding surface 12 between the rotary disk 20 and valve seat (first valve element 10), i.e. the microfluidic channel structures 22 b, 23 b, 24 b, 25 b, referred to as throttle channel structures, are completely located in the disk 20.

The valve seat 10 itself contains the main outlet 11, 102. By rotating the disk 20 on the valve seat 10, the flow through the valve 100 can be completely stopped or one of the microfluidic channel structures 22 b, 23 b, 24 b, 25 b can be released. A channel structure/rotary position can thereby also be configured such that no significant throttling takes place (passage).

Functional Definition

Fluidics in General

If it is functionally differentiated between

-   -   Directional control valves (switching valves): valves with         several switch positions that completely block, release or         interconnect the fluid between different connections.     -   Flow valves: valves which reduce or completely block the flow         area. In the simplest case, the flow here changes depending on         the pressure difference:         -   Orifice valve (short orifice distance)             -   Rigid             -   Adjustable         -   Throttle valve (longer throttle distance)             -   Rigid             -   Adjustable

The present invention can thus be regarded as a directional control valve with integrated, differently designed rigid throttles.

While adjustable flow valves typically only change the effective cross-section locally at one point (compare needle valve), in the present case, microfluidic channel structures are “switched”, i.e. depending on the switching stage, different fluid paths may also be flowed through. If the present invention is compared with a needle valve, for example, the differences are shown in Table 1.

TABLE 1 Comparison needle valve with present invention. Needle valve Present invention Continuous switching process N discrete switching stages Mechanical precision and Only the precision of the positioning accuracy of the microfluidic channel structures actuator determine the determines the achievable flow achievable flow accuracy. accuracy. Limited dynamic range: Unlimited dynamic range: It is not practicable to map The actuator can-independent very small and large flows of the flow rate to be realized- in a valve: approach the switch positions Small flow needs precise in the same way, since the change mechanics because of the in flow rate is completely realized smallest valve gap, this precise by the respective microfluidic mechanics, however, is channel. too slow for larger flows.

In other words—with relatively coarse valve actuators, even small mass flows can be precisely throttled.

Refrigeration

In refrigeration, the following valve types may be used as “small” (expansion) valves:

-   -   Directional valves based on rotatable disks (on/off only)     -   Directional control valves in general (only on/off or pulse         width modulation)     -   Needle valves (continuous adjustability)     -   Flow valves based on rotatable discs (at least as patent)

Further Technical Embodiments

Underlying Directional Valve

The implementation forms A and B can be understood as a combination of a (macroscopic) directional valve based on a rotary disk and (microscopic) microfluidic channels for throttling.

Alternatively, it would also be possible to use any other (translatory, rotary, . . . ) directional valve as a basis, as long as the used number of switching stages is made available.

Drive

It is suggested to use a stepper motor to drive the rotary disk 10, 20. Basically, other types of drives could also be used here.

Interconnection of the Channel Structures

Basically, the microfluidic channel structures, similar to an electrical resistance network, can be interconnected in different ways:

-   -   a) Individually (see FIGS. 1A to 1D and 2A and 2B)     -   b) Serially (see FIGS. 3A, 3B, 4A, 4B)     -   c) Parallel (see FIGS. 5A, 5B, 6A, 6B)     -   d) as well as combinations of a)-c) (see FIG. 7)

For both implementation forms A and B, the channel structures are individually connected according to a).

Arrangements of the channel structures in relation to the rotary disk

The implementation forms A and B differ with regard to the arrangement of the channel structures:

-   -   Closed channel structure below the rotary disk (implementation         form A)     -   Closed channel structure in the rotary disk (implementation form         B)

In principle, the microfluidic channel structures can also be arranged as follows:

-   -   Open channel structure on the lower side of the rotary disk         (rotating on the valve seat)     -   Open channel structure on the upper side of the valve seat         (rotary disk slides over)

Possible Additional Functionalities/Especially Refrigeration

-   -   Control/regulation by device electronics     -   Valve contains “bypass” which is opened during vacuum drawing in         production (better/faster vacuum production in the refrigeration         cycle, avoidance of long vacuuming times or double-sided vacuum         drawing on the high and low pressure side).     -   Integration of the dryer: valve contains substances such as         zeolite which can absorb moisture in sintered form or bulk         material and thus take over the function of the dryer:         -   Substances can fulfil a filter function for particles.         -   Materials can be placed in the valve or in the pipe             connection.         -   Materials can be configured such that they can be changed             without replacing the valve.     -   Upstream or downstream partial or basic throttling:         -   Valve contains e.g. sintered body (possibly as part of the             dryer). The sintered body can take over a partial or basic             throttling so that the channels can be designed larger and             to avoid the pollution problem.         -   The same could of course also be achieved by, for example,             constricting the inlet or outlet of the valve or adding a             filter, sintered body, precapillary, etc.     -   Valve contains particle filter         -   The particle filter can be arranged so that it is not             necessary to replace the valve.     -   Welded valve body     -   Positioning of the valve in the refrigeration cycle         -   Type of fastening     -   Fluid         -   Refrigerant can be gaseous/liquid or vaporous

In the following, conceivable designs of the expansion valve 100 according to the invention are once again summarized in key points:

-   -   Throttle valve 100 for fluids that block or throttle a fluid         flow,     -   wherein the throttle valve contains 100 microstructured elements         22 a, 22 b, 23 a, 23 b, 24 a, 24 b, 25 a, 25 b, 26 a, 26 b,     -   wherein the throttling takes place in discrete stages,     -   wherein the inflowing fluid flow is blocked by an actuator or is         interconnected to one or more microchannels,     -   wherein the microchannels within the valve lead again into a         single outflowing fluid flow,     -   wherein the throttle function is mainly generated by the flow         resistance of the micro-channel,     -   wherein, in addition to throttling the interconnectable         microchannels, a part of the throttling (basic throttling) is         generated by a component (resistor) which is upstream or         downstream and through which flow occurs,     -   wherein no or only one microchannel is active (individual         switching) in each case,     -   wherein the valve is a rotary valve,     -   wherein the microchannels are integrated into the rotary disk:         -   disk with channels is rotatable, or     -   wherein the microchannels are located below the rotary disk:         -   channels are not rotatable.

An embodiment of the above mentioned implementation form A (FIGS. 1A to 1D) is shown in FIG. 9. This embodiment of an expansion valve 100 according to the invention has a single-stage gear reduction with a first gear 91 and a second gear 92 engaging therewith. The second gear 92 is shown in more detail in the magnified illustration at the top right. It is connected mechanically and advantageously non-rotatably to the first valve element 10.

The illustration at the bottom right shows a magnified view of the second valve element 20 consisting of a first part 20 b and a second part 20 a. The channel structures, and in particular the throttle channel structures 22 b, 23 b, 24 b, can be contained in the upper plate part 20 a as shown.

The channel structures, and in particular the throttle channel structures 22 b, 23 b, 24 b, can also be formed in the lower plate part 20 b or, if applicable, in both plate parts 20 a, 20 b.

The configuration of the channel structures or throttle channel structures 22 b, 23 b, 24 b in the upper plate part 20 a can have production advantages. Starting from the inlet bore, the throttle channels 22 b, 23 b, 24 b lead to a collecting channel 55 (with no or hardly any throttling) which in turn leads to the outlet 102. The control of the inlets is realized via a recess 11 in the rotary disk (first valve element) 10.

An embodiment of the above mentioned implementation form B (FIGS. 2A and 2B) is shown in FIG. 10. This embodiment of an expansion valve 100 according to the invention also has a single-stage gear reduction with a first gear 91 and a second gear 92 engaging therewith.

The second gear 92 is shown in more detail in the magnification (illustration on the right). The second gear 92 forms the second part 20 a of the second valve element 20. The rotary disk 20 b shown below, which is mechanically and advantageously non-rotatably fixed to the second gear 92, forms the first part 20 b of the second valve element 20.

The channel structures, and in particular the throttle channel structures 22 b, 23 b, 24 b, can be formed as shown in the upper part 20 a of the two-part second valve element 20. Alternatively or additionally, the channel structures, and in particular the throttle channel structures 22 b, 23 b, 24 b, however, can also be configured in the lower part 20 b of the two-part second valve element 20, or if applicable, also in both parts 20 a, 20 b of the two-part second valve element 20.

Advantageously, channel structures are provided in the upper or lower part 20 a, 20 b of the two-part second valve element 20. A seal 93, e.g. a Teflon flat seal, can be arranged between the two parts 20 a, 20 b of the two-part second valve element 20.

Further embodiments of the invention may provide:

-   -   Five instead of the three throttle channels shown here, plus an         above described “open” position, plus a known above described         “stop” position     -   Energetically arranged switching stages in optimum sequence     -   Filter structures or retention elements

The channel structures 22 a, 22 b; 23 a, 23 b; 24 a, 24 b; 25 a, 25 b described above may be clogged by particles 210 larger than the channel area. A clogging completely reduces or stops the flow through the expansion valve 100 and thus changes the overall operating behavior.

In order to prevent this, filter structures or retention elements 200 may be attached stream of the expansion valve 100,

-   -   on/in the valve housing 30,     -   at the inlet to/within the channel structures (see later         “collector channel structure”)

A filter structure or retention element 200 typically consists of a large number of pores which are smaller than the particles 210 to be filtered out. The particles 210 which are larger than the pores of the filters 200can therefore neither penetrate nor permeate the filter structure 200. This effect is called the sieve effect. Due to the large number of parallel pores, one or more blocked pores do not or only slightly reduce the flow through the filter 200. The pores do not necessarily have to be the same size.

The filter structure or the retention element 200 can be configured such that it does not cause any significant throttling of the fluid flow (e.g. refrigerant). However, the filter structure or the retention element 200 can also be configured such that, in addition to the downstream throttle channel structures 21 b to 27 b, it generates part of the total throttling, i.e. the retention element 200, for example, generates 20% of the maximum throttling in a fixed manner, and the downstream throttle channel structures 21 b to 27 b generate the remaining 0% -80%, depending on the switch position.

The filter structure or retention element 200 can also serve as a moisture collector (e.g. together with zeolite) to remove residual moisture from the refrigeration system.

Filter systems 200 can be realized e.g. by perforated plates, sintered materials, fabrics, nets, open-pored sponges, etc. but also by channel structures, and in particular by the filter channel structures described above.

Wth respect to such filter channel structures 222 a to 222 u, a filter effect can be generated by a filter structure consisting of parallel filter channel structures (input channels) 222 a to 222 u which have the same or smaller dimensions than the subsequent channel structure (throttle channel structure) 21 b to 27 b and are bundled back onto the relevant channel, wherein the input channels do not necessarily all have to be the same in cross-section and length, as already described above with reference to FIGS. 11 to 16. If, for example, the channel structure has a cross-section of 50×40, then both 40×40 could function as a filter, but also 100×30, i.e. it is not advisable to refer to a smaller “cross-section” in respect of the input channels.

The channel structures 11, 22 a, 22 b, 102 also do not necessarily have to be uniform, e.g. having a constant diameter. Asymmetric or other geometries are also possible, e.g. conical or alternating inner diameters, which applies to all of the channel structures 11, 22 a, 22 b, 102 described above.

If an input channel (filter channel structure) 222 a to 222 u is blocked by a particle 210, the fluid can still flow in through the other input channels 222 a to 222 u. The number and size of input channels 222 a to 222 u can also be selected so that input channels 222 a to 222 u, which are clogged to a certain extent, do not reduce the flow rate or only slightly reduce it.

In any case, with an expansion valve 100 according to the invention, other filters can also be used instead of the parallel input channels (filter channel structures) 222 a to 222 u described below. The parallel input channels 222 a to 222 u can form a filter structure or a retention element 200 that has larger and/or fewer pores (thus pores are channels here) than other known filter types. A filter structure according to the invention (retention element) 200 can be realized in different ways, e.g.

-   -   mechanically, e.g. by milling, embossing or drilling,     -   made of open-pored, foamed or sintered materials,     -   composed of multi-layer screen structures,     -   consisting of a bulk of uniform small bodies.

Such a filter structure 200 shown in FIG. 12 with parallel input channels 222 a to 222 g can be individually connected upstream of each relevant channel, and in particular of each throttle channel structure 22 b, 23 b, 24 b, 25 b.

In the following, the arrangement of the filter channel structures 222 a to 222 u is exemplarily described on the basis of the view of the lower part 20 b of the two-part second valve element 20 shown in FIG. 2A.

Compatibility of filter concepts with respect to the variants of the expansion valve 100 described above:

Valve variants (variant B, see FIGS. 2A and 2B) which have throttle channel structures 21 b to 27 b in the rotatable disk 20 a, 20 b:

-   -   basically compatible (see FIG. 2A)

Valve variants (variant A, see FIGS. 1A to 1D) with channel structures 21 b to 27 b below the rotatable disk 20 a, 20 b:

-   -   parallel input channels 222 a to 222 u individually possible         upstream of each channel (FIG. 11)     -   all other concepts could include the integration of the filter         channel structure 222 a to 222 u into the rotatable disk 20 a,         20 b.

It is also possible to connect several or all relevant channel structures to a central filter structure (collector channel structure) 230 as shown in FIG. 13.

A possibly existing “open” position, i.e. a position in which there is no or almost no throttling by the channel structures, can be independent of this. Such an “open” position is illustrated, for example, by switching stage 6 with a larger cross-section as shown in FIG. 13.

In addition to the flow resistance of the channel structures themselves, further geometrical changes in the flow course can generally lead to additional throttling (additional pressure losses) which depend on the flow velocity and density of the fluid and are sufficiently known in the technical literature. These include, for example:

-   -   (stepwise) constrictions in the cross-section     -   (stepwise) extensions in the cross-section     -   arcs     -   deflections     -   . . .

Another arrangement with a central filter structure (retention element) 200 is shown in FIG. 14. The advantage of this arrangement is that, on the one hand, only one filter structure or one retention element 200 are used and, on the other hand, channel length can be saved because channel structure segments I_(a) to V_(a) and I_(b) to V_(b) can be used several times for the various switching stages:

Stage/position 1: minimum flow/maximum throttling

Stage/position 2: maximum flow/minimum throttling

Stage 1: Channel segments Va+IVa+IIla+IIa+Ia+Ib

Stage 2: Channel segments Va+IVa+IIla+IIa+IIb

Stage 3: Channel segments Va+IVa+IIla+IIIb

Stage 4: Channel segments Va+IVa+IVb

Stage 5: Channel segments Va+Vb

However, it is also conceivable that the filter structure or the retention element 200 is connected to a broader “collector channel structure” without throttle function 26 b or 230, as shown in FIG. 15, which can simultaneously realize the “open” position already mentioned, in this case switching stage 6.

Such an “open” position can have several functions:

-   -   It enables faster evacuation of the refrigerant cycle before         charging with refrigerant, as no or no significant throttling         takes place.     -   It can be used during operation as a defrost function, i.e. the         compressor builds up pressure when the valve is closed in “stop”         position 0, the refrigerant becomes hot, the valve moves to         “open” position 6 and the evaporator is flooded with warm         refrigerant. Such a defrost function can also be supported by a         conventional electric heater. Furthermore, this function can be         performed depending on the door openings or the time or a user         input in order to start defrosting at an uncritical time, e.g.         with regard to noise generation.     -   It can be used to clean the filter structure and pass particles         through the valve as a flushing function, as described below.

Further Measures to Retain Particles

It would also be conceivable that the refrigerant flow is guided by suitable means 250 (FIG. 18) in such a way that zones 252 are formed in the valve interior space in which particles carried along can settle, e.g. if the valve interior space is characterized by

-   -   Means 250 which control the refrigerant flow such that zones         252, 253 are formed in which particles 210 carried along can         settle (e.g. baffle walls 251, pipe extensions 255 or additional         installation space extensions 255). Important for the         implementation of the desired filter effect are a strong         reduction of the flow velocity, almost up to the idleness and as         large a distance as possible between inflow and outflow in this         area.     -   Means which are partly (<100%) in the fluid flow (e.g.         refrigerant) and which are able to fix particles (e.g. filters).         The cold flow can still pass almost without throttling.     -   These means (filters) can be located in these “settling zones”.

Basically, a filter/channel structure 222 a to 222 u can only retain a limited amount of particles 210 without significantly reducing the flow through the expansion valve 100. For example, from a certain loading of particles 210 the complete filter 200 is clogged and particles 210 are removed, e.g. through the expansion valve 100.

If the filter structure or the retention element 200 is configured such that the channel structure 26 b used for the “open” position passes the retention element 200, as shown in FIG. 16, the fluid (e.g. refrigerant) flows past the retaining element 200 after switching to the “open” position 6. Particles 210 can thus be carried away, passed through the expansion valve 100 and thus flushed out again by the retention element 200, since the “open function” 26 b provides considerably larger channel areas for throttling than the throttle channel structures 21 b to 25 b.

It would furthermore be conceivable that, as with the defrost function mentioned above, when the expansion valve 100 is closed, pressure is built up specifically via the compressor and then suddenly reduced via the “open” position.

Such a flushing function can be performed automatically at regular intervals. Alternatively, the following scheme can also be used to identify whether and when such a flushing function shall be applied:

-   -   1) The unit notices, e.g. on the basis of air temperature,         evaporator temperature, compressor running time, compressor         switching stage, ambient temperature, pressure and/or         combination of the parameters, that cooling capacity is lacking.     -   2) Flushing function is activated.     -   3) If the flushing function is successful, normal further         operation.     -   4) If the flushing function is not successful, emergency         function, i.e. other e.g. next higher channel is used.

Further measures for removing particles at the inlet side

Furthermore, by suitable constructive measures

-   -   the direction of flow through the filter/channel structure can         be reversed in one switch position and thus flushed free again;     -   particles 210, i.e. if, for example, the inlets of the filter or         channel structures are located at the disk circumference and a         stationary stripping structure is present at one point         (advantageously at the start or end stop) which strips past the         circumference like a brush when the disk is rotated.

In both cases, the particles 210 are probably still on the “inlet side” and can settle again if applicable, but the filter/channel gets free and, if reversed again, they would probably not stick to the same place and could be flushed out through the “open” position.

Further measures to remove and flush particles through the valve

Furthermore, by suitable constructive measures

-   -   the cross-section of one or more filter channels 222 a to 222 u         or throttle channels 21 b to 27 b are temporarily enlarged in a         switch position so that blocking particles 210 can optionally be         guided through the expansion valve 100:     -   by using an additional level in the cover plate 20 a of the         expansion valve 100, the flow channel could be enlarged by a         bypass channel 223 (FIG. 17) on a regular basis or also for a         short time for special control requirements by a suitable rotary         mechanism so that the particles 210 can be flushed through the         structure. The channel overlap of throttle channel and bypass         channel 223 are at least at the inlet and outlet 224, 227 of the         throttle channel 21 b . A trapezoidal channel shape which leads         into the bypass channel 223 would be advantageous to support the         outflow of the particle 210 via the parallel connection of a         sufficiently large channel.     -   In addition, inlet and outlet 224, 227 of the throttle channels         21 b should be installed at the same distance and in the same         direction in the rotary disk, as thereby, the bypass channel 223         can be used for all throttle channels 21 b , 22 b, 23 b arranged         in this way. In contrast, a throttle channel 21 b , 22 b, 23 b         can also be configured such that it remains unaffected by the         bypass channel 223.     -   Flushing is carried out by lifting off the cover plate 20 a:     -   There is a rotary position of the rotary disk 20 b having the         throttle channel structures 22 b, 23 b, 24 b in relation to the         rotary disk 20 a (FIG. 2A) in which both rotary disks 20 a, 20 b         are lifted off from one another to a maximum distance and thus         release a sufficiently large channel for evacuating or flushing         the expansion valve 100.     -   Said lift-off can be realized mechanically, magnetically or         hydraulically, e.g. before or after reaching a stop or reference         position.     -   The tightness of the channel structures can be fixedly realized         which means that by lifting off the plates 20 a, 20 b, only the         throttle channel inlet is released, since particles 210 which         lead to the clogging of the channel essentially remain stuck         there, or there is a flexible seal which is released by lifting         off both plates 20 a, 20 b and then closed again.     -   When arranged at a stop position, lifting off both plates 20 a,         20 b could close the expansion valve 100 on a separate sealing         surface, which may facilitate sealing the channel structures         together and improving the stop function. The flushing of the         structure would then be realized via the refrigerant between the         throttle channel and the closed inlet or via the refrigerant         inlet when the valve is opened.

Arrangement of the Switching stages (FIGS. 21A to 21D)

It is apparent that significant additional functions/operational qualities of the expansion valve 100 according to the invention can be generated by the arrangement and type of the various switching stages:

-   -   i. A flushing function as described above.     -   ii. Reduced energy consumption through energy-efficient         arrangement of the switching stages and minimization of stepper         motor operation.     -   iii. Reduced noise development by minimizing stepper motor         operation.

Wth a classic expansion valve based on a stepper motor-controlled needle valve, the flow rate increases from the closed state when the stepper motor is activated, i.e. the throttling is reduced.

This means that starting from the number of steps N=0 (closed state), the throttling is successively reduced with each step until the minimum throttling (=maximum flow through the expansion valve) is reached at the number of steps N=N_(max), i.e. the throttling is proportional to the number of N steps performed. Consequently, in order to reach a certain throttle stage, all lower throttle stages are passed through, even if they are not actually needed. To close such a conventional expansion valve, the number of N steps driven is reduced accordingly.

The expansion valve 100 according to the invention as described above offers more possibilities as schematically shown in FIGS. 21A to 21D. Starting from a stop position (blocking switch position 380) N=0, the flow can be adjusted by arranging the switching stages.

-   -   continuously linearly increasing (FIG. 21A)     -   continuously linear descending (FIG. 21B)     -   can be defined arbitrarily (non-linearly) (FIG. 21C)

It is also possible to use any area between the switching stages as a stop position. However, one or more “broader” stop positions can also be realized (FIG. 21D).

Wherein then e.g.

N=0: Switching stage 0

N=10: Switching stage 1

N=20: Switching stage 2

FIG. 21D shows stop positions and an exemplary arrangement around the stop position according to the frequency of use: 1 most frequently, 6 least frequently.

Insofar as the stepper motor has no position return, which possibly may be realized by an incremental encoder or by purely electronic measures, it is to be taken into account that possibly no step jump may have taken place despite the step command. Therefore, at regular intervals, a movement to a defined stop should take place in order to “zero” the step position. Such a stop can generally be located at N=0 and N=N_(max).

Ideally, the arrangement of the switching stages 381 to 386 starting from a stop position 380 should therefore be such that, on the one hand, frequently used switching stages are approached with as few steps as possible and, at the same time, a stop position is approached regularly, ideally without additional step travel, wherein:

-   -   Frequently used switching stages are those switching stages         which are used in normal operation, e.g. several times a day.         Less used switching stages are, for example, the “open         function”, which is only used during production and, if         applicable, later for flushing out particles or for defrosting.         This also includes the switching stage for commissioning the         device.

This also takes into account the fact that, for example, during compressor operation, it is advantageous to switch successively from one switching stage to one or more other switching stages in order to, for example

-   -   dynamically adjust the flow rate and thus the cooling capacity         to the requirements,     -   to ensure that the pressure in the evaporator decreases rapidly         towards the end of compressor operation and then continues to         run constantly and ideally.

A further aspect of the expansion valve 100 according to the invention includes the fact that the passing through or loosening particles 210 through the expansion valve 100, past the channel structures 21 b , is carried out by selectively lifting off the entire disk (e.g. first valve element 10) from the valve seat (e.g. second valve element 20) at one or more rotary positions, as sketched exemplarily in FIGS. 19A and 19B. At the same time, the open position can be realized.

While this invention has been described in terms of several embodiments, there are alterations, permutations, and equivalents which will be apparent to others skilled in the art and which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention. 

1. An expansion valve for reducing a pressure of a fluid flowing through the expansion valve along a fluid flow path, the expansion valve comprising: at least one fluid inlet and at least one fluid outlet, a first valve element comprising at least one first channel structure, and a second valve element comprising at least one second channel structure and one third channel structure, wherein the first valve element and the second valve element are movable relative to each other, wherein, in a first position of the valve elements, the first channel structure and the second channel structure are aligned with each other and form a first fluid flow path comprising a first flow resistance between the fluid inlet and the fluid outlet, wherein, in a second position of the valve elements, the first channel structure and the third channel structure are aligned with each other and form a second fluid flow path comprising a second flow resistance differing from the first flow resistance between the fluid inlet and the fluid outlet, and wherein the second channel structure comprises a first variable or constant flow area, and wherein the third channel structure comprises a second variable or constant flow area differing from the first flow area, wherein the different flow areas oppose different flow resistances to the fluid and throttle the flow rate of the fluid to different extents.
 2. The expansion valve according to claim 1, wherein the amount of throttling of the flow rate of the fluid is determined by the flow resistance of the individual channel structures.
 3. The expansion valve according to claim 1, wherein the first channel structure in the first valve element extends at least in sections in the axial direction, and/or wherein the second and third channel structures in the second valve element extends at least in sections in the radial direction and/or in the axial direction, and wherein the radial portions contribute the major proportion to throttling the fluid flowing through the channel structures.
 4. The expansion valve according to claim 1, wherein the first valve element comprises a surface facing the second valve element and wherein the second valve element is movable relative to the first valve element in a plane parallel to said surface.
 5. The expansion valve according to claim 1, wherein the second valve element is configured in two parts, wherein a first part of the second valve element comprises at least a portion of the second and third channel structures and the fluid outlet, wherein these portions of the second and third channel structures within the first part of the second valve element are each connected to the fluid outlet, and/or wherein the first valve element is rotatably arranged on the second valve element, and wherein by means of a rotary positioning of the first channel structure one of the second and third channel structures is released by the first channel structure being aligned in different positions of the valve elements selectively to one of the second and third channel structures formed in the second valve element, and/or wherein the second and third channel structures each lead into a circumferential channel structure interconnecting the second and third channel structures and forming a common supply to the fluid outlet.
 6. The expansion valve according to claim 5, wherein at least one portion of said second and third channel structures is arranged within the second part of the two-part second valve element, and wherein the first part of the two-part second valve element comprises the fluid outlet, and at least one further portion of the second and third channel structures is formed within the first part of the two-part second valve element and is connected to the fluid outlet by means of the circumferential channel structure, or wherein the first part of the two-part second valve element comprises the fluid outlet, and the second and third channel structures are formed within the second part of the two-part second valve element and each are connected to the fluid outlet by the circumferential channel structure.
 7. The expansion valve according to claim 1, wherein the expansion valve comprises a cover, the cover being immovably connected to the first valve element, and the second valve element being movably arranged within the cover relative to the first valve element, and wherein the first channel structure forms the fluid outlet of the expansion valve, and wherein one of the second and third channel structures is released in each case by means of rotary positioning of the second valve element on the first valve element, by selectively aligning in different positions of the valve elements in each case one of the second and third channel structures of the second valve element with the first channel structure of the first valve element.
 8. The expansion valve according to claim 1, wherein in the first and second positions of the valve elements, in each case exactly one of the second and third channel structures of the second valve element is aligned with the first channel structure of the first valve element to form a single fluid flow path between the fluid inlet and the fluid outlet.
 9. The expansion valve according to claim 1, wherein the second channel structure and the third channel structure are interconnected within the second valve element at least in sections, wherein in the second position of the valve elements the second fluid flow path is composed of the second and third channel structures connected thereto, and the second fluid flow path comprises a total flow resistance composed of the flow resistance of the second channel structure and the flow resistance of the third channel structure connected thereto, or wherein the first valve element comprises at least one fourth channel structure, and wherein in the first position of the valve elements, the third channel structure and the fourth channel structure are additionally aligned with each other and form a third fluid flow path comprising a third flow resistance between the fluid inlet and the fluid outlet.
 10. The expansion valve according to claim 1, wherein the expansion valve comprises a retention element for retaining a particle located in the fluid, and wherein the retention element comprises at least two filter channel structures which are each fluidly coupled to at least one throttle channel structure, and wherein the cross-section of the filter channel structures is smaller than or equal to the cross-section of the throttle channel structure fluidly coupled thereto in each case, and/or wherein at least one filter channel structure and at least one throttle channel structure each comprise an angular cross-section and at least one side of the angular filter channel structure is smaller than or equal to a shortest side of the angular throttle channel structure, and/or wherein at least one filter channel structure and at least one throttle channel structure each comprise a circular cross-section, the cross-section of the round filter channel structure being smaller than the cross-section of the circular throttle channel structure.
 11. The expansion valve according to claim 10, wherein a collector channel structure is arranged between the filter channel structures and the throttle channel structures which collector channel structure is respectively fluidly coupled to the filter channel structures and at least one throttle channel structure so that a fluid flowing in through at least one filter channel structure is collected in the collector channel structure and is passed on to at least one throttle channel structure.
 12. The expansion valve according to claim 11, wherein the throttle channel structure with the largest cross-section of all throttle channel structures is connected and fluidly coupled to the filter channel structures, said throttle channel structure being arranged upstream of the filter channel structures in the fluid flow direction, and/or wherein the expansion valve can be brought into a plurality of positions, wherein in a free-flow switch position the throttle channel structure with the largest cross-section of all throttle channel structures forms the fluid flow path through the expansion valve, and wherein in a blocking switch position, a fluid flow path is blocked.
 13. The expansion valve according to claim 12, wherein the expansion valve is configured to provide a defrost function by the expansion valve first being in the blocking switch position, wherein the pressurized fluid heats, and the expansion valve is subsequently brought into the free-flow switch position, wherein an evaporator fluidly coupled to the expansion valve is flooded with the heated fluid.
 14. The expansion valve according to claim 1, wherein the expansion valve can be brought into a blocking switch position and into a plurality of flow switch positions by means of the relative movement between the first and the second valve element, wherein the expansion valve in each flow switch position provides a fluid flow path comprising different flow resistance between the fluid inlet and the fluid outlet, respectively, and wherein in the blocking switch position, a fluid flow path is blocked between the fluid inlet and the fluid outlet, and wherein the individual flow switch positions, starting from the blocking switch position, are arranged in ascending or descending order relative to their respective flow resistance so that in the event of a relative movement of the two valve elements from one switch position to the respective next switch position, the respective flow resistance increases or decreases, and/or wherein the individual flow switch positions are arranged, starting from the blocking switch position, in an order with respect to their respective flow resistance, this order depending on how often the respective switch position is used in operation.
 15. A refrigerator and/or freezer comprising an expansion valve according to claim
 1. 